1. Chapter 14
Chemical Reactions
Preview
CRCT Preparation

2. Chapter 14
CRCT Preparation
1. The diagram shows how a light stick works. Light sticks begin to glow when the vial inside the stick is broken. Chemicals inside the vial mix with chemicals outside of the vial. Which of the following statements best supports the idea that a chemical reaction is occurring?
A The vial is broken into smaller pieces.
B Energy is released in the form of light.
C Two different substances are combined.
D The substances are in a flexible container.

3. Chapter 14
CRCT Preparation
1. The diagram shows how a light stick works. Light sticks begin to glow when the vial inside the stick is broken. Chemicals inside the vial mix with chemicals outside of the vial. Which of the following statements best supports the idea that a chemical reaction is occurring?
A The vial is broken into smaller pieces.
B Energy is released in the form of light.
C Two different substances are combined.
D The substances are in a flexible container.

4. Chapter 14
CRCT Preparation
2. A scientist at the Chemical Analysis Core Facility at the University of Georgia’s Athens campus carries out a reaction in a test tube. After the bubbling stops, she notices that the test tube is very warm. What might she conclude about the reaction?
A The reaction happened very quickly.
B The reaction is endothermic.
C The reaction is exothermic.
D No reaction took place.

5. Chapter 14
CRCT Preparation
2. A scientist at the Chemical Analysis Core Facility at the University of Georgia’s Athens campus carries out a reaction in a test tube. After the bubbling stops, she notices that the test tube is very warm. What might she conclude about the reaction?
A The reaction happened very quickly.
B The reaction is endothermic.
C The reaction is exothermic.
D No reaction took place.

6. Chapter 14 3. Which of the following contains one oxygen atom? A H2O
CRCT Preparation
3. Which of the following contains one oxygen atom?
A H2O
B CO2
C 2N2O
D Co

7. Chapter 14 3. Which of the following contains one oxygen atom? A H2O
CRCT Preparation
3. Which of the following contains one oxygen atom?
A H2O
B CO2
C 2N2O
D Co

8. Chapter 14
CRCT Preparation
4. Some silverware is made with the element silver (Ag). Over time, this silverware will turn black if it is not cleaned with a special solution. Which of the following statements best explains why the element silver in the silverware turns black?
A It absorbs energy when exposed to warm food.
B It breaks down into smaller and smaller particles.
C It reacts with substances in the air to form a new substance.
D It changes from one state of matter into another state of matter.

9. Chapter 14
CRCT Preparation
4. Some silverware is made with the element silver (Ag). Over time, this silverware will turn black if it is not cleaned with a special solution. Which of the following statements best explains why the element silver in the silverware turns black?
A It absorbs energy when exposed to warm food.
B It breaks down into smaller and smaller particles.
C It reacts with substances in the air to form a new substance.
D It changes from one state of matter into another state of matter.

10. Chapter 14
CRCT Preparation
5. Which chemical equation correctly shows the formation of water from hydrogen and oxygen?
A H2 + O2 → H2O
B 2H2 + O2 → 2H2O
C H2 + 2O → H2O
D H + O2 → H2O

11. Chapter 14
CRCT Preparation
5. Which chemical equation correctly shows the formation of water from hydrogen and oxygen?
A H2 + O2 → H2O
B 2H2 + O2 → 2H2O
C H2 + 2O → H2O
D H + O2 → H2O

12. Chapter 14
CRCT Preparation
6. The energy diagram shows the progress of a chemical reaction. Which of the following statements about this reaction is true?
A Energy is absorbed during this reaction.
B The rate of this reaction increases, then it decreases.
C The reaction is exothermic.
D Activation energy is not required in this reaction.

13. Chapter 14
CRCT Preparation
6. The energy diagram shows the progress of a chemical reaction. Which of the following statements about this reaction is true?
A Energy is absorbed during this reaction.
B The rate of this reaction increases, then it decreases.
C The reaction is exothermic.
D Activation energy is not required in this reaction.

14. Chapter 14
CRCT Preparation
7. Which of the following is an example of a chemical change?
A water freezing into ice
B ice melting into water
C meat spoiling and changing color
D butter softening into a liquid

15. Chapter 14
CRCT Preparation
7. Which of the following is an example of a chemical change?
A water freezing into ice
B ice melting into water
C meat spoiling and changing color
D butter softening into a liquid

16. Chapter 14
CRCT Preparation
8. Which of the following is true of the law of conservation of energy?
A The law of conservation of energy states that energy cannot change forms.
B The law of conservation of energy states that energy cannot be created or destroyed.
C The law of conservation of energy states that the total energy of the reactants is greater than the total energy of the products.
D The law of conservation of energy states that the total energy of the reactants is less than the total energy of the products.

17. Chapter 14
CRCT Preparation
8. Which of the following is true of the law of conservation of energy?
A The law of conservation of energy states that energy cannot change forms.
B The law of conservation of energy states that energy cannot be created or destroyed.
C The law of conservation of energy states that the total energy of the reactants is greater than the total energy of the products.
D The law of conservation of energy states that the total energy of the reactants is less than the total energy of the products.

18. Chapter 14
CRCT Preparation
9. Look at the equations. Which of the following statements is true?
A Equation 1 is an endothermic reaction.
B Both equations 1 and 2 are endothermic reactions.
C Equation 2 is an endothermic reaction.
D Both equations 1 and 2 are exothermic reactions.

19. Chapter 14
CRCT Preparation
9. Look at the equations. Which of the following statements is true?
A Equation 1 is an endothermic reaction.
B Both equations 1 and 2 are endothermic reactions.
C Equation 2 is an endothermic reaction.
D Both equations 1 and 2 are exothermic reactions.

20. Chapter 14
CRCT Preparation
10. What are three ways by which the rate of a chemical reaction can be increased?

21. Chapter 14
CRCT Preparation
10. Answer - Full-credit answers should include three of the following points. The rate of a chemical reaction can be increased by:
• increasing the temperature
• increasing the surface area of the reactants
• increasing the concentration of the reactants
• adding a catalyst

22. Chapter 14
CRCT Preparation
11. Compare synthesis and decomposition reactions and give an example of each.

23. Chapter 14
CRCT Preparation
11. Answer - Full-credit answers should include the following points:
• In a synthesis reaction, two or more substances combine to form a new compound.
• In a decomposition reaction, a compound breaks down into two or more simpler substances.
• Examples may vary. An example of a synthesis reaction is the reaction of sodium with chlorine to produce sodium chloride. An example of a decomposition reaction is carbonic acid breaking down into water and carbon dioxide.