1. Chapter 4
Elements, Compounds, and Mixtures
Preview
CRCT Preparation

2. Chapter 4
CRCT Preparation
1. Which two substances in the table are most likely the same?
A substances A and C
B substances B and D
C substances C and D
D substances A and D

3. Chapter 4
CRCT Preparation
1. Which two substances in the table are most likely the same?
A substances A and C
B substances B and D
C substances C and D
D substances A and D

4. Chapter 4 CRCT Preparation
2. You are given two jars, each of which contains an unknown substance. You are asked to determine if the substances are different from one another or if each jar contains the same substance. What should you do to complete this task?
A Compare the appearances of the substances. If the substances look the same, then they are the same.
B Compare only the physical properties of the substances. If the substances have the same density or melting point, then they are the same.
C Compare both the physical and the chemical properties of the substances. If the substances perform the same in a variety of tests, then they are the same.
D Compare the physical states of the substances. If the substances are in the same state, then they are the same.

5. Chapter 4 CRCT Preparation
2. You are given two jars, each of which contains an unknown substance. You are asked to determine if the substances are different from one another or if each jar contains the same substance. What should you do to complete this task?
A Compare the appearances of the substances. If the substances look the same, then they are the same.
B Compare only the physical properties of the substances. If the substances have the same density or melting point, then they are the same.
C Compare both the physical and the chemical properties of the substances. If the substances perform the same in a variety of tests, then they are the same.
D Compare the physical states of the substances. If the substances are in the same state, then they are the same.

6. Chapter 4
CRCT Preparation
3. If two poisonous elements are combined chemically, which of the following will be true of the resulting compound?
A The compound will be more poisonous than the gases.
B The compound will be as poisonous as the gases.
C The compound may or may not be poisonous.
D The compound will not be poisonous.

7. Chapter 4
CRCT Preparation
3. If two poisonous elements are combined chemically, which of the following will be true of the resulting compound?
A The compound will be more poisonous than the gases.
B The compound will be as poisonous as the gases.
C The compound may or may not be poisonous.
D The compound will not be poisonous.

8. Chapter 4
CRCT Preparation
4. Ellen made the illustration to show one of the steps in her most recent experiment. Which statement describes what Ellen was doing during this step of the experiment?
A She was using a chemical change to break down a compound into the elements that make it up.
B She was using a physical change to separate the compounds that make up an element.
C She was using a physical change to separate the components that make up a mixture.
D She was using a chemical change to combine elements to form a compound.

9. Chapter 4
CRCT Preparation
4. Ellen made the illustration to show one of the steps in her most recent experiment. Which statement describes what Ellen was doing during this step of the experiment?
A She was using a chemical change to break down a compound into the elements that make it up.
B She was using a physical change to separate the compounds that make up an element.
C She was using a physical change to separate the components that make up a mixture.
D She was using a chemical change to combine elements to form a compound.

10. Chapter 4
CRCT Preparation
5. The graph was constructed from data collected during a laboratory investigation. Which of the following values is the amount of sodium nitrate that can dissolve in 100 mL of water at 40°C?
A 0 g
B 40 g
C 100 g
D 130 g

11. Chapter 4
CRCT Preparation
5. The graph was constructed from data collected during a laboratory investigation. Which of the following values is the amount of sodium nitrate that can dissolve in 100 mL of water at 40°C?
A 0 g
B 40 g
C 100 g
D 130 g

12. Chapter 4
CRCT Preparation
6. Ka-wai makes a solution which contains the maximum amount of sodium chlorate that can dissolve in 100 mL of water at 0°C. He heats the solution to 60°C. How much additional sodium chlorate must he add to once again have a solution that has the maximum amount of sodium chlorate dissolved in it at this new temperature?
A 2 g
B 40 g
C 50 g
D 80 g

13. Chapter 4
CRCT Preparation
6. Ka-wai makes a solution which contains the maximum amount of sodium chlorate that can dissolve in 100 mL of water at 0°C. He heats the solution to 60°C. How much additional sodium chlorate must he add to once again have a solution that has the maximum amount of sodium chlorate dissolved in it at this new temperature?
A 2 g
B 40 g
C 50 g
D 80 g

14. Chapter 4
CRCT Preparation
7. Which of the following sentences best describes table salt, NaCl?
A Table salt is a compound made from two elements.
B Table salt is a mixture made from two elements.
C Table salt is an element made from two mixtures.
D Table salt is an alloy made from a metal and a nonmetal.

15. Chapter 4
CRCT Preparation
7. Which of the following sentences best describes table salt, NaCl?
A Table salt is a compound made from two elements.
B Table salt is a mixture made from two elements.
C Table salt is an element made from two mixtures.
D Table salt is an alloy made from a metal and a nonmetal.

16. Chapter 4
CRCT Preparation
8. Imagine that you were asked to classify four samples of equal and known volume, each of which was made up of a single element. Which factor would be most useful for identifying them?
A mass
B shape
C hardness
D original source

17. Chapter 4
CRCT Preparation
8. Imagine that you were asked to classify four samples of equal and known volume, each of which was made up of a single element. Which factor would be most useful for identifying them?
A mass
B shape
C hardness
D original source

18. Chapter 4
CRCT Preparation
9. Rafiq has a container filled with a clear liquid. He knows that the liquid is either a compound or a mixture but does not know which. What can Rafiq do to find out? Explain your answer.

19. Chapter 4
CRCT Preparation
9. Answer - Full credit answers should include the following points:
• Mixtures can be separated by physical means but compounds cannot.
• Rafiq should try to separate the liquid into different substances by physical means, such as distillation, centrifuging, or evaporation.
• If Rafiq can separate the liquid into different substances by physical means, it is a mixture.
• If Rafiq cannot separate the liquid into different substances by physical means, it is probably a compound.

20. Chapter 4
CRCT Preparation
10. Compare elements and compounds. How are they similar and how are they different? List two examples of each kind of substance.

21. Chapter 4
CRCT Preparation
10. Answer - Full credit answers should include the following points:
• Both elements and compounds are pure substances, which means that they are substances in which there is only one type of particle.
• An element is a pure substance that cannot be separated into simpler substances.
• A compound is a pure substance that is composed of two or more elements that are chemically combined. Com-pounds can be separated into simpler substances by chemical means.
• Students should give two examples of elements, such as carbon, oxygen, or gold, and two examples of compounds, such as water, carbon dioxide, or table salt.