midterm review sheet – Flashcards
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| Define Chemistry |
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| Chemistry is the study of the composition, structure, and properties of matter, the processes that matter undergoes, and the energy changes that accompany these processes. |
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| If you were studying properties of diamonds (diamonds are made of carbon), you would be studying ______ chemistry. |
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| organic |
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| If you were studying how the intake of potassium affects the production of ATP, you would be studying ______ chemistry. |
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| biochemistry |
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| If you were studying the energy given off by a combustion reaction, you would be studying _____ chemistry. |
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| physical |
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| If you were studying how oxygen binds to hemoglobin (contains iron), you would be studying __________ chemistry. |
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| inorganic |
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| If you were studying the composition of wool to determine how to make clothes softer, you would be studying _______ chemistry. |
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| analytical |
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| If you used computers to put together a model that showed the destruction of the ozone layer, you would be studying _________ chemistry. |
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| theoretical |
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| Use the definitions of basic research and applied research to distinguish the two terms. |
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| Basic research is carried out for the sake of increasing knowledge, such as how or why a specific reaction occurs and what the properties of a substance are. On the other hand, applied research is generally carried out to solve a problem. |
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| What is the benefit of technological development? Name one example of technological development in our society. |
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| The benefit is that it improves the quality of our lives. EX: biodegradable materials, computers, air conditioning |
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| Define matter. Define mass. |
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| Matter- anything that has mass and takes up space. Mass- a measure of the amount of matter. |
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| What are the four basic building blocks of matter? |
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| atom, element, compound, molecule |
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| Define element. |
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| element- a pure substance that cannot be broken down into simpler, stable substances and is made of one type of atom. |
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| Define atom |
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| the smallest unit of an element that maintains the chemical properties of that element. |
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| What are extensive properties? Give one example |
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| Extensive properties depend on the amount of matter present. EX: volume, mass, amount of energy in a substance |
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| What are intensive properties? Give an example. |
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| Intensive properties do not depend on the amount of matter present. EX: melting point, boiling point, density, color, texture, hardness |
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| Four physical properties of a classroom desk. |
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| 1) three feet off the ground 2) tan colored 3) solid 4) flat surface |
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| What are three physical changes involved in cooking? |
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| 1) cutting 2) melting 3) boiling |
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| List two changes of state. Are changes of state classified as physical or chemical changes? |
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| 1) melting 2) boiling Changes of state are classified as physical changes. |
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| Solids have a _________ volume and __________ shape. |
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| Solids have a definite volume and a definite shape. |
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| Liquids have a ______ volume and _________ shape. |
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| Liquids have a definite volume and an indefinite shape. |
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| Gases have a ______ volume and _______ shape. |
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| Gasses have an indefinite volume and an indefinite shape. |
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| What is the main difference between a physical property and a chemical property? |
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| A physical property is a characteristic that can be observed or measured without changing the identity of the substance, whereas a chemical property relates to a substances ability to undergo changes that transform it into different substances. Physical properties can be observed without changing the identity of the substance, chemical properties can not. |
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| List three chemical changes involved in cooking |
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| baking chicken, grilling hamburgers, frying shrimp |
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| Chemical changes involve reactants and products. What is the difference between these two terms. |
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| Chemical changes begin with reactants which turn into products |
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| The law of conservation of mass states that the mass of the _______ must equal the mass of the _______. |
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| The law of conservation of mass states that the mass of the reactants must equal the mass of the products. |
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| Matter can be divided into two categories. What are they? |
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| 1) pure substances 2) mixtures |
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| What is the difference between a homogeneous mixture and a heterogeneous mixture? Give an example of each. |
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| homogeneous is consistent throughout (sweet tea) heterogeneous is not consistent throughout (salsa) |
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| An _________ like lithium or a ________ like salt can both be considered pure substances. |
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| An element like lithium or a compound like salt can both be considered pure substances |
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| A compound can be broken down into elements by what kind of change? |
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| a chemical change |
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| Horizontal rows on the periodic table are called _________. |
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| periods |
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| Vertical columns on the periodic table are called _________. |
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| groups |
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| What is the scientific method? |
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| A logical approach to solving problems |
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| List the four steps to the scientific method. |
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| observe, hypothesize, experiment, conclude |
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| There are two types of data. What are they? How can you tell the difference between the two? |
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| 1) qualitative - data that deals with descriptive information 2) quantitative- data that deals with numerical information |
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| When testing a hypothesis the experimenter should use controls, why? |
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| To have a way to compare the results of your experiment |
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| Use the definition of dependent variable and independent variable to distinguish the two terms. |
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| dependent variable- the variable that changes because of the independent variable independent variable- the variable that is changed by the scientist |
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| If you were to do an experiment to test to see which paper towel was the most absorbent, list three controls. |
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| 1) amount of paper towel used 2) amount of liquid used 3) type of liquid used |
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| Based on the paper towel experiment, what would be the independent variable and the dependent variable? |
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| independent variable- paper towel brand dependent variable- how much liquid was absorbed |
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| What is the next step if the hypothesis is not supported by the experiment? |
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| Either revise or reject the hypothesis. |
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| What is a theory? What is a hypothesis? |
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| theory- a broad generalization that is supported by many experiments hypothesis- a testable statement |
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| What two things make up a measurement? |
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| 1) number 2) unit |
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| The SI Units are used across the world for science. Why is it important that scientists all use the same units? |
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| So that scientists across the world use the same units which allows results to be shared |
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| List the seven SI base units. |
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| meter, gram, second, kelvin, mole, ampere, candela |
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| How are the base units manipulated to account for large and small measurements? |
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| prefixes are added |
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| How does mass differ from weight? |
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| mass is not dependent on gravity, weight is |
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| What does volume measure? List three units for volume. |
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| Volume measures the amount of space an object takes up. Units for volume: 1) cm cubed 2) mL 3) L |
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| What is the formula for density? What is the unit for density? |
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| D= m/v density = mass divided by volume. the unit for density is g/mL or g/cm^3 |
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| Can density be measured directly? How did we determine the density of a penny in the penny lab? |
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| No. In the penny lab we used a scale to find the mass, then the water displacement method to find volume. We then calculated density with the formula. |
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| Why does ice float in water? |
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| Ice has a lower density than water. |
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| Convert 435g to mg. |
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| 435,000 mg |
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| convert 3.54 cm^3 to L. |
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| 3.54cm^3 = 3.54mL = 0.00354 L |
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| What is the difference between accuracy and precision? |
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| accuracy- the closeness of a measurement to the accepted value precision- the closeness of a set of measurements to each other |
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| Are the following test scores accurate, precise, neither or both? 74, 70, 76 |
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| They are precise but not accurate |
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| What does the percent error tell you about your experiment? Is a high percentage or a low percentage a more accurate experiment? |
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| How close your data is to the accepted data. A low % is a more accurate experiment |
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| If the actual value for the density of copper is 7.34 g/mL and the value you recorded after your lab was 8.42 g/mL, what is the percent error of your experiment? |
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| [(accepted-experimental)/accepted]*100 [(8.42-7.34)/7.34]*100=14.7% |
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| How many significant figures in each of the following numbers? a) 52.5200 b)3003 c)20300 d)3.500 e)0.00254 f)900 g)200500.0 h)8290 i)0.00520 |
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| a)5 b)4 c)3 d)4 e)3 f)1 g)7 h)3 i)3 |
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| Who was the first person to believe that matter was made up of smaller particles? |
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| Democritus |
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| Was Democratis supported? why or why not? |
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| no, there was no proof for his ideas |
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| Why did it take nearly 2,000 years before anyone developed these ideas of whether matter is made of smaller particles or not? |
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| It was not until then that there was technology that allowed proof |
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| State the laws of definite and multiple proportions; be able to identify both on the exam. |
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| law of definite proportions- a compound contains the same elements in the same proportions by mass regardless of the size or source of the compound law of multiple proportions- if two or more different compounds are composed of the same two elements, then the ratio of the masses of the second element combined with a certain mass of the first element is always in a ratio of small whole numbers |
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| Who developed atomic theory? |
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| Dalton |
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| What is the first statement of the atomic theory? |
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| all matter is composed of small particles called atoms |
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| What are the two modifications that have been made to the atomic theory? |
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| 1) atoms are divisible 2) not all atoms of the same element are identical |
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| Define atom |
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| the smallest particle of an element that retains the chemical properties of that element |
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| What are the three subatomic particles that make up the atom? |
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| proton, neutron, and electron |
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| Who discovered that subatomic particles existed by performing the cathode ray experiment? |
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| Thomson |
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| How did scientists determine that the cathode ray was composed of negatively charged particles? |
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| When a negative plate was put up to the glass tube, the cathode ray inside bent away from the negative charge. |
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| Describe the setup of Rutherford's gold foil experiment. |
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| Rutherford shot alpha particles at a sheet of gold foil, the experiment was surrounded by zinc sulfide which would flash if hit by the alpha particle. |
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| What surprised scientists when observing the gold foil experiment? |
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| That some of the alpha particles hit the gold foil and bounced back |
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| What result of the gold foil experiment proved that the atom was made mostly of empty space? |
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| Most of the alpha particles went straight through undisturbed. |
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| What result of the gold foil experiment proved that the nucleus was dense? |
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| Whatever caused the large alpha particle to stop and change direction must be massive, a large mass and a small volume means that the particle is dense |
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| What result of the gold foil experiment proved that the nucleus was positively charged? |
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| The positive charged alpha particles were deflected. Like charges repel one another |
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| What do nuclear forces do? |
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| They hold the nucleus together |
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| What two particles are located inside the nucleus? |
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| proton and neutron |
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| The number of protons in an atom can also be called the ________. |
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| atomic number |
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| Isotopes differ in two ways. What are the two ways? |
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| 1) number of neutrons 2) mass |
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| Name three ways that isotopes are the same. |
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| 1) number of protons 2) number of electrons 3) chemical behavior |
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| The total number of protons and neutrons can also be called the ______. |
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| mass number |
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| What does amu stand for? |
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| atomic mass unit |
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| The unit amu is based on which isotope? |
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| carbon-12 |
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| Identify the mass in amus for the proton, neutron, and electron |
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| proton = 1 amu neutron = 1 amu electron = 0 amu |
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| List three types of electromagnetic radiation. |
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| gamma rays, X-rays, UV rays |
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| List the one thing that all waves have in common. |
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| They all travel at the speed of light. (3.00 *10^8 m/s) |
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| List three ways that waves are different. |
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| 1) wavelength 2) frequency 3) energy |
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| Describe the difference between frequency and wavelength. |
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| wavelength- the distance between equivalent points on adjacent waves frequency- the number of waves that pass a given point in one second |
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| Wavelength and frequency are related ________. |
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| indirectly |
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| Energy and frequency are related _________. |
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| directly |
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| Who first came up with the idea that energy was emitted as particles not as waves? |
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| Planck |
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| Einstein came up with the dual __________-___________ nature for electromagnetic radiation. |
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| dual wave-particle nature. |
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| What is a photon? |
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| a particle of electromagnetic radiation carrying a quantum of energy |
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| Describe how an electron moves from ground state to excited state and back to ground state. |
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| An electron in its lowest energy state is in its ground state, when it absorbs energy it moves to an excited state, it gives off a photon and moves back to ground state. |
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| What is released when an electron moves from excited state to ground state? |
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| a photon |
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| What is the difference between ground state and excited state? |
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| ground state- lowest energy level excited state- higher energy level |
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| Each atom has its own ___________ ________________ ______________ that can be used to identify the element, much like a fingerprint. |
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| atomic emission spectrum |
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| How did Bohr describe the movement of electrons? |
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| moved around the nucleus in organized orbits like planets orbit around the sun |
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| The further the electron is away from the nucleus the ( more / less ) energy it has. |
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| more |
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| What is the difference between absorption and emission? |
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| absorption- taking in energy emission- giving off energy |
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| What three scientists contributed to the current Quantum Model of the Atom? |
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| de Broglie, Heisenberg, Schrodinger |
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| What is predicted by the Schrodinger equation? |
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| the probability of finding an electron in a given orbital |
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| State the Heisenberg Uncertainty Principle |
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| The position and velocity of an electron cannot be determined simultaneously. |
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| What is an atomic orbital? |
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| a region of space where an electron is likely to be found |
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| How many energy levels are possible in an atom? |
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| 7 |
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| Each energy level contains sub levels. What are the four sub-levels and their shapes? |
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| 1) s -sphere 2) p -dumbbell 3) d -4 leaf clover 4) f -complicated |
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| Each sub-level contains orbitals. How many orbitals are in each type of sub-level? |
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| s-1 p-3 d-5 f-7 |
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| How many electrons are required to fill the first energy level? |
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| 2 |
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| How many electrons can go into the third energy level? |
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| 18 |
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| What information can be determined from the description 5s^2? |
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| electrons are located in the 5th energy level in a spherical shaped sub-level and there are 2 electrons present. |
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| How is a nuclear equation different from a chemical equation? (give at least two differences) |
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| nuclear equations- change atoms from reactant to product; give off large amounts of energy chemical equations- atoms stay the same from reactant to product; give off small amounts of energy |
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| What are the main subatomic particles involved in a chemical equation? |
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| electrons |
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| What are the main subatomic particles involved in a nuclear equation? |
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| protons and neutrons |
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| Which type of reaction, chemical or nuclear, give larger releases of energy? |
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| nuclear |
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| What are the three types of radiation? |
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| alpha, beta, and gama |
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| Rank the three types of radiation from most massive to least massive. |
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| alpha, beta, gamma |
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| Rank the three types of radiation from most penetrating to least penetrating. |
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| gamma, beta, alpha |
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| How did Rutherford determine that there were three types of radiation? |
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| placed a positive and negative plate above and below a radioactive substance; beta was attracted to the positive plate, alpha was attracted to the negative plate, and gamma was unaffected |
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| What was Roentgen's contribution to nuclear chemistry? |
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| developed the X-ray |
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| What was Becquerel's contribution to nuclear chemistry? |
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| determined that radioactive substances spontaneously give off radiation |
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| What was the Curie's contribution to nuclear chemistry? |
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| isolated radium and plonium |
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| Cobalt-60 has a half-life of 5.27 years. How much of a 165g sample remains after 26.35 years? |
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| 5.16 g |
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| How are fission and fusion similar? |
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| fission and fusion are both nuclear processes. |
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| How are fission and fusion different? |
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| fission- splitting of a large atom to release energy fusion- joining of smaller atoms to release energy |
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| What are the only two fissionable isotopes? |
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| uranium and polonium |
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| How is fission a chain reaction? |
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| fission begins when a neutron hits an unstable uranium atom. When this reaction is complete, 3 neutrons are given off allowing the reaction to continue. |
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| How is the speed of the fission reaction controlled in a nuclear reactor? |
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| by using control rods to absorb neutrons and slow down the reaction |
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| The reactor heats the water which generates steam. The steam turns the _____ which generates _____. |
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| turbine; electricity |
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| What is the only substance that produces energy from fusion? |
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| the sun |
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| What are the current limitations that are keeping us from using fusion as a main power source? |
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| temperature required is very high; also, we have to develop a container to hold this extremely high temperature. |
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| What is a spent fuel rod? |
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| a rod that use to contain fissionable uranium atoms, but has used all the uranium |
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| What is done with the spent fuel rods after they are removed from the nuclear reactor? |
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| they are put in spent fuel pools (swimming pools) |
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| What are some benefits to using nuclear reactors to make energy compared to other methods? |
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| cheap, release no harmful gases into atmosphere, easy to do |
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| What are some drawbacks to using nuclear reactors to make energy compared to other methods. |
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| give radioactive product that must be stored, plants are expensive to build |
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| What is the unit used to measure the dose of radiation absorbed by humans? |
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| rem |
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| What are three methods used to detect radiation? |
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| film bodge, Geiger counter |
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| List 5 uses of nuclear chemistry. |
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| bombs, X-rays, cancer treatment, to make energy, smoke detectors |
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| ______ came up with arranging the elements in order of their repeating properties. He arranged the elements in order of increasing atomic mass. |
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| Mendeleev |
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| _______ later revised the periodic table by arranging the elements in order of increasing _____ ________. |
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| Moseley; atomic number |
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| State the periodic law. |
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| when the elements are arranged in order of increasing atomic number their properties will repeat. |
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| What is the name of group 1 elements? |
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| Alkali metals |
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| What is the name of group 2 elements? |
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| Alkaline Earth metals |
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| What is the name of group 17 elements? |
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| Halogens |
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| What is the name of group 18 elements? |
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| Noble Gases |
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| What is the name of groups 3-12? |
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| transition metals |
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| What are the names of the two rows that make up the f-block? |
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| Lanthanides and Actinides |
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| What are metalloids? Where are they located on the periodic table? |
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| substances that have properties of both metals and nonmetals |
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| List three properties of metals. Where are they located on the periodic table? |
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| good conductors, malleable, ductile; to the left of the stair-step line |
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| list three properties of nonmetals. Where are they located on the periodic table? |
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| bad conductors, not malleable, brittle; right of the stair-step line |
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| List three properties of s-block metals. |
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| soft, very reactive, good conductors |
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| List two properties of p-block metals. |
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| harder than s-block metals, not as reactive as s-block metals |
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| list four properties of d-block metals. |
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| shinny, good conductors, hard, malleable |
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| Explain why group 18 is referred to as the noble gases? |
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| because their outer energy level is full and they do not interact (bond) with any other elements |
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| Explain what the atomic radius measures. |
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| distance from nucleus to edge of electron cloud |
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| How is the atomic radius of an atom actually measured? |
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| distance between 2 nuclei divided by 2 |
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| What is the period trend or the atomic radius? The group trend? |
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| period trend= decreases to the right group trend= increases going down |
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| Rank the following elements from largest radius to smallest radius: Cl, I, Br, C, F, Li |
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| I, Br, Cl, Li, C, F |
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| What is the group trend for ionic radius? |
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| increases as go down groups |
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| What is the difference between a cation and an anion? Include how each is formed. |
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| -cation is a positive ion that forms when electrons are lost -anion is a negative ion that forms when electrons are gained |
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| What is the period trend for ionization energy? The group trend? |
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| period: increases to the right group: decreases going down |
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| What is ionization energy? |
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| the energy required to remove an electron from an atom |
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| When an electron is removed from an element a ( cation / anion ) is formed. Are metals or nonmetals more likely to do this? |
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| cation; metals |
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| What is electronegativity? |
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| the attraction for electrons in a chemical bond |
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| What is the most electronegative element? |
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| fluorine |
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| Why do elements bond? |
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| to become stable |
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| What electrons are involved in the bonding process? |
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| valence electrons |
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| What types of elements are combined in a compound? what type of bonding? List one example of a compound. |
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| metal and nonmetal; ionic; NaCl |
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| List three properties of ionic compounds. |
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| high melting point, conduct when liquid, brittle |
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| What is the overall charge of ionic compounds? |
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| zero (neutral) |
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| How are ionic bonds formed? |
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| metal cation is attracted to a nonmetal anion |
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| Why can ionic compounds not conduct electricity in the solid state? |
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| because the anions are not free to move; surrounded by cations |
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| What is a cation? Give an example. |
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| an ion with a positive charge Ex: Mg 2+ |
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| What is an anion? Give an example? |
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| An ion with a negative charge. Ex: O2- |
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| Why, when writing the name of a compound that contains a transition metal, does a Roman numeral have to be included? |
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| Because transition metals do not always form the same ion; the correct one is indicated with a Roman numeral |
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| What is a binary compound? All binary compounds, whether ionic or covalent, will end with what suffix? |
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| a combination of 2 elements; will end with -ide |
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| What is a polyatomic ion? |
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| an ion composed of more than one atom. |
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| What is the term used in metallic bonding that describes the fact that electrons do not belong to one particular atom? |
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| delocalized electrons |
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| Why are electrons delocalized in metals? |
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| because the outer energy levels overlap |
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| Why are metals good conductors of heat and electricity? |
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| because the delocalized electrons are free to move |
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| Why are metals shiny? |
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| because delocalized electrons are free to move |
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| What types of elements are combined in a molecule? what type of bonding? List one example of a molecule. |
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| nonmetal and nonmetal; covalent; CO2 |
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| What is a diatomic molecule? |
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| a molecule containing 2 atoms EX: Cl2 or CO |
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| Which bonds are stronger, ionic or covalent? |
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| ionic |
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| What would melt first, a block of ice or a grain of salt? Why? |
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| block of ice; ice is covalent and salt is ionic; because ionic is stronger than covalent, covalent will melt first |
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| How many electrons are shared in a single bond? |
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| two |
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| How many electrons are shared in a double bond? |
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| 4 |
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| How many electrons are shared in a triple bond? |
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| 6 |
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| Rate single, double, and triple bonds from longest to shortest. From strongest to weakest. |
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| longest-shortest: single, double, triple strongest-weakest: triple, double, single |
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| What is the difference between a lone pair of electrons and a shared pair of electrons? |
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| lone pair belong only to one atom, shared pair is shared between two atoms |
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| State the octet rule |
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| each atom will lose, gain, or share to achieve 8 electrons in their outer energy level |
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| What are the two exceptions to the octet rule? |
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| Hydrogen and helium (they only want 2, not 8) |
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| What three things must be checked in order for a Lewis structure to be correct? |
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| total number of electrons, octet rule, used correct number of atoms |
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| Lewis structures represent molecules in 2D, in order to represent molecules in 3D what theory must be used? |
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| VSEPR theory |
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| What is the VSEPR theory? |
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| describes the 3D arrangement of atoms in a molecule |
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| When assigning variables to molecules in order to determine the VSEPR shape, what does A represent? What does B represent? what does E represent? |
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| A- central atom B- atoms bonded to central atom E- lone pairs of electrons on the central atom |
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| Why do the trigonal planar and bent shapes have bond angles less than 109.5?? |
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| because more than one correct lewis structure can be drawn |
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| Polar bonds and nonpolar bonds are the two types of covalent bonds. How are they different? Give an example of each. |
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| polar bonds- electrons shared unequally (partial charges present) EX: H-F nonpolar bonds- electrons shared equally (no partial charge present) EX: O-O |
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| How is an intermolecular force different from an ionic or covalent bond? |
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| intermolecular forces occur between molecules; intro molecular forces (ionic and covalent) occur within molecules |
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| List three types of intermolecular forces |
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| dispersion, dipole, hydrogen bonding |
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| How can you determine the strength of a covalent bond? |
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| electronegativity difference |
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| Hydrogen bonding occurs when hydrogen bonds to which 3 elements? |
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| F, O, N |
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| London dispersion forces exist between ________ molecules. |
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| all |
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| Dipole-dipole forces exist only between _____ molecules. |
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| polar |
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| Why are partial charges used in polar molecules? |
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| there is an unequal distribution of electrons |
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| How is it determined which atom in the bond gets the partial negative charge? |
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| the more electronegative atom gets the partial negative. |
