Chapter 2 – Chemistry Test Questions – Flashcards
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Unlock answers| four molecules that make up 96% of living organisms |
| hydrogen (H) Carbon (C) Oxygen (O) and Nitrogen (N) |
| what is matter? |
| anything that occupies space and has mass |
| what is mass? |
the quantity of matter an object has. mass is not the same as weight |
| elements |
pure substances that connot be broken down chemically into simpler kinds of matter each element has a specfic symbol, which consists of one or 2 letters, called its chemical symbol |
| atoms |
atoms are the simplest unit of an element that retains all the same properties of that element consists of 3 distinct parts called subatomic particles the center of the atom is called the nucleus |
| nucleus |
composed of 2 subatomic particles: protons and neutrons protons have positive charge neutrons has neutral charge (no charge) consists of the mass of the atom |
| protons |
the number of protons= atomic number # of protons identifies the element the positive charge of the proton is balanced by the negative charge of the electron electron energy levels: those in the outermost layer have more energy than ones in the inner levels
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| electrons |
surrounding the nucleus is the elcectron cloud has a negative charge and constanly move around the nucleus the mass of the electron is so small that it is not even considered when calculating the mass of an atom
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| neutrons |
| nuetrons= atomic mass= atomic number |
| atomic number |
| # of protons |
| atomic weight |
| protons + neutrons |
| valence electrons |
the electrons in the outermost level are called valence electrons the valence electron will determine how an element will behave chemically
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| compounds |
pure substance made up of two or more elements Ex: NaCl Sodium Chloride :) |
| molecule |
| is the simplest part of a substance that retains all of the properties of the substance and can exist in a free state |
| chemical bonds |
the sharing or transferring of electrons b/w two electrons (how molecules are made) 2 types of bonding: covelant and ionic |
| covalent bonding |
formed when two atoms share one or more pairs of electrons (may have single, double or triple bonds between atoms)
Some covalent bonds form polar molecules, which mean that they have a slightly positive and a slightly negative side.
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| polarity |
the oxygen region is slightly negative hydrogen region is slightly positive atoms are not arranged in a staright line |
| ions |
an atom that has lost or gained an electron in it outer shell (very unstable) and now carries a charge.
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| ionic bonding |
| formed when electrons are gained or lost |
| cation |
| a postively charged ion |
| anioin |
| negitavly charged ion |
| hydrogen bonding |
bond between hydrogen atoms already covelantly bonded in a molecule to oppositely charge particles (water molecules) weak bond that can be easily broken causes water to cling to itself |
| chemical reaction |
| simply the making and breaking of bonds |
| chemical equation |
the way a reaction is described in writing has 3 basic components: reactants, products and arrow |
| reactants |
| the ions or molecules that go into the reaction |
| products |
| the outcome of the reaction |
| arrow |
| describes the direction the reaction is going |
| 3 types of chemical reaction |
| sythesis, decomposition, and exchange |
| synthesis reaction |
building a more complex molecule from many simple ones Requires energy |
| decomposition reaction |
a more complex molecule broken down into many smaller ones releases energy |
| exchange reaction |
atoms are exchanged between molecules energy is not required or released. |
| what factors influence the rate of chemical reactions? |
| catalysts, temperature, concentration, and surface of the reactants |
| catalysts |
is a protein is destroyed or used up during a reaction speeds up the reaction AKA and enzyme |
| inorganic molecules |
does not contain hydrocarbon groups often has ionic bonding |
| solutes |
| substances that are being dissolved |
| solvent |
| the liquid that dissolves the substances |
| solution |
| mixture of the solute and the solvent |
| concentration |
a measurment of the amount of solute dissolved in a fixed amount of solution
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| saturated solution |
| a solution in which no more solute can dissolve |
| hydrophilic |
| water loving (usually polar molecules or ions that dissolves or mixes well with water) |
| hydrophobic |
| water hating (usually neutral, non polar molecules such as lipids) |
| electrolytes |
| salts in their ionic form that have the ability to trasmit an electrical charge |
| dissociation |
| the breaking apart of a water molecule into 2 ions of opposite charge (does not equal ionization) |
| ionize |
| ionically bonded substances, that when added to water, it breaks apart into their invidual ions |
| acids |
1 to 6 if the number of hydrogen ions in a solution is greater than the number of hydroxide ions, the solution is acid |
| bases |
5 to 14 if the number of hydroxide ions is greater than the number of hydronium ions, the solution is a base base=alkaline |
| neutral |
7 blood=7.4 |
| buffers |
chemical substances that neutralize small amounts of acids or bases helps to maintaim pH of body fluids at normal levels |
| organic molecules |
conatins hydrocarbon groups whuch are made up of carbon atom carbon atoms covalently bonded to other carbon atoms, hydrogen, oxygen and nitrogen divided into 4 groups: carbs, protein, lipids, and nucleic acids |
