Chemistry Unit 1 Review

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Explain why air is classified as matter
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Although air is \”invisible,\” it has mass and occupies space
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The Japanese characters for chemistry literally mean \”change study.\” Why are these appropriate characters to represent chemistry?
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Chemistry is concerned with the changes that matter undergoes.
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Describe the main difference between inorganic chemistry and organic chemistry
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Organic chemistry is the study of chemicals that contain carbon; inorganic chemistry is the study of chemicals that do not contain carbon.
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Was Wallace Carothers doing pure chemistry or applied chemistry when he discovered nylon? Explain your answer
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Pure chemistry; His experiments tested a hypothesis of another chemist. His results led to applied chemistry—the large-scale production of nylon
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Why would a firefighter or a reporter need to understand chemistry?
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A firefighter needs to know which chemicals to use to fight different types of fires; knowledge of chemistry will help a reporter gather information during an interview with a chemist.
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Explain how chemists were able to connect the ability of aspirin to relieve pain to its ability to reduce the risk of a heart attack
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The group of chemicals in the body that produce pain are also involved in the formation of blood clots. Aspirin blocks the production of these chemicals.
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George de Mestral used burrs as a model for his hook-and-loop tapes. Using burrs as an example, explain the difference between a macroscopic and a microscopic view of matte
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In a macroscopic view you can see an object like a burr with the unaided eye; to observe the tiny hooks on a burr’s surface requires magnification (a microscopic view).
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How does the use of insulation help to conserve energy?
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Insulation acts as a barrier to heat flow. If heat flow is reduced, energy is conserved.
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What is the overall goal of scientists who work with biotechnology?
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To understand the structure of matter found in cells and chemical changes that occur in cells
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Describe two ways that biotechnology can be used to treat diseases.
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Gene therapy and production of chemicals such as insulin
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How can testing soil help to increase the productivity of farmland?
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Testing reveals if soil contains the right chemicals to grow a crop and suggest way to improve soil.
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What is a pollutant?
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A pollutant is a material found in air, soil, or water that is harmful to living organisms
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Why is it important that young children not be exposed to lead-based paint?
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Lead poisoning can cause nervous system damage, especially in growing children.
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How can scientists study the composition of distant stars?
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By analyzing the light they transmit to Earth
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How can scientists study the composition of distant stars?
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They based their conclusions on experimental evidence.
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What is the most powerful tool that any scientist can have?
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The scientific method
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What is the purpose of an experiment?
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To test a hypothesis
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Which of the following is not a part of the scientific method? A. hypothesis B.experiment C.guess D.theory
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C
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How do a manipulated variable and a responding variable differ?
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The manipulated variable is changed during an experiment; the responding variable is observed during an experiment.
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You perform an experiment and get unexpected results. According to the scientific method, what should you do next?
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Repeat the experiment. If you get the same result, you must propose a new hypothesis.
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Explain how the results of many experiments can lead to both a scientific law and a theory.
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A scientific law summarizes the results of many experiments; a theory explains them.
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List two general reasons why scientists are likely to collaborate.
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To share knowledge across disciplines and resources between industry and academia
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Identify the statements that correctly describe good problem solvers. A.Read a problem only once. B.Check their work. C.Look up missing facts. D.Look for relationships among the data
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b, c, and d
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What do effective problem-solving strategies have in common?
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Developing a plan and implementing that plan
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In which step of the three-step problem-solving approach for numeric problems is a problem-solving strategy developed?
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Step 1, analyze
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On the average, a baseball team wins two out of every three games it plays. How many games will this team lose in a 162-game season
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54 games (one third of 163)
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If your heart beats at an average rate of 72 times per minute, how many times will your heart beat in an hour? In a day?
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4320 times an hour, 103,680 times a day
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How many days would it take you to count a million pennies if you could count one penny each second?
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12 days
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Match each area of chemistry with a numbered statement. a.physical chemistry b.organic chemistry c.analytical chemistry d.inorganic chemistry e.biochemistry 1.Measure the level of lead in blood. 2.Study non-carbon-based chemicals in rocks. 3.Investigate changes that occur as food is digested in the stomach. 4.Study carbon-based chemicals in coal. 5.Explain the energy transfer that occurs when ice melts.
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Answers will vary, but possible answers are 1c, 2d, 3e, 4b, and 5a
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Explain why chemistry might be useful in a career you are thinking of pursuing
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Answers will vary but should demonstrate an understanding that chemistry is the study of matter and the changes it undergoes.
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Explain how chemistry has affected the ability of this athlete to compete
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One possible answer is development of the materials to product an artificial lim
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What type of chemist might study how an athlete uses energy during a competition? Give a reason for your answer.
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Students are likely to choose biochemist because biochemistry is the study of processes that take place in organisms. However, a student might choose physical chemist because physical chemistry include the study of energy transfer as matter undergoes a change.
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A doctor examines a patient’s sore throat and suggests that the patient has strep throat. She takes a sample to test for the bacteria that cause strep throat. What parts of the scientific method is the doctor applying?
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The doctor’s hypothesis is that the sore throat is the result of bacteria that cause strep throat. She tests the hypothesis by testing a sample of the presence of the bacteria.
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You perform an experiment and find that the results do not agree with an accepted theory. Should you conclude that you made an error in your procedure? Explain.
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Your experiment may be correct, but your hypothesis may be wrong. You should reexamine your hypothesis and repeat the experiment.
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A student is planning a science fair project called Does Temperature Affect How High a Basketball Can Bounce? A.Based on the project title, identify the manipulated variable and the responding variable. B.Name at least two factors that would need to be kept constant during the experiment.
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a. The manipulated variable is the temperature of the basketball. The responding variable is the height of the basketball’s bounce. b. The method for dropping the basketball before it bounces; the method for measuring the height of the bounce
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Pure water freezes at 0°C. A student wanted to test the effect of adding salt to the water. The table shows the data that was collected.
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a. amount of salt added b. freezing point c. Changing the volume of the water would also change the concentration of the salt solution and affect the results. d. Yes, to a point. The freezing point appears to be leveling off at about 15ºC.
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In the time a person on a bicycle travels 4 miles, a person in a car travels 30 miles. Assuming a constant speed, how far will the car travel while the bicycle travels 40 miles?
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300 miles
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Compare and contrast the study of chemistry with the study of a language
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One possible answer is that with both areas of study, students slowly build up a vocabulary and a set of concepts that relate the new terms. Both areas rely on a systematic approach—grammar versus the scientific method. Chemistry deals with matter and words do not qualify as matter. Science is independent of a specific culture; language varies from culture to culture.
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Comment on the idea that science accepts what works and rejects what does not work
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A possible answer is that scientists accept hypotheses that are supported by experimental results and reject hypotheses that are not supported by experimental results.
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You are asked to design an experiment to answer the question: \”Which paper towel is the best?\” a.What is the manipulated variable in your experiment? b.List three possible responding variables that could be used to define \”best\”? c.Pick one of the responding variables and rewrite the question as a hypothesis. d.List at least five factors that must be kept constant when you test the hypothesis
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a. the brand of paper towel b. Possible answers include strongest, most absorbent, strongest when wet, largest area per sheet, and easiest to tear from roll. c. Sample answer: The best towel will absorb the most liquid. d. Possible answers include size of paper towel sample, type of liquid, method for measuring absorbency, method for measuring strength.
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Important discoveries in science are sometimes the result of an accident. Louis Pasteur said, \”Chance favors the prepared mind.\” Explain how both of these statements can be true.
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A person who is educated in the theories and practice of chemistry would be more likely to recognize the significance of an accidental discovery and have the means and motivation to develop that accidental discovery into an important scientific contribution.
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Four beakers have a total weight of 2.0 lb. Each beaker when full holds 0.5 lb of water. Describe two different methods you could use to calculate the weight of two full beakers of water. Then try both methods and compare the answer
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Divide the weight of 4 beakers by 2 or multiply the weight of 1 beaker by 2 (2.0 Ibs/2 or 0.5 lb x 2 = 1 lb).
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Explain what is wrong with the statement, \”Theories are proven by experiments.\”
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A theory can never be proven. It is a well-tested explanation of a broad set of observations. A theory may need to be changed in the future to explain new observations.

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