Rate of Chemical Reaction

Which of the following statements BEST describes COLLISION THEORY?

• A. Atoms or molecules must collide with a sufficient amount of energy in order to react.

• B. Catalyst can be recovered unchanged at the end of process.

• C. Increasing the concentration of a reactant increases the rate of reaction.

• D. Smaller pieces have a greater surface area, thus, providing much greater contact among the reactants and effecting more collisions.

2. The amount of energy required to break the bonds between the reacting molecules is known as _____.

• A. Activated Complex

• B. Activation Energy

• C. Collision Theory

• D. Law of Conservation of Mass

3. What refers to the PEAK of the energy diagram for a chemical reaction?

• A. Activated Complex

• B. Activation Energy

• C. Collision Theory

• D. Law of Conservation of Mass

4. When a lit match touches the wick of a candle, it begins to burn. When the match is removed, the candle continues to burn. The match __________.

• A. behaves as a catalyst

• B. increases the concentration

• C. lowers the activation energy barrier

• D. supplies the activation energy

5. Which of the following is a SLOW chemical reaction?

• A. rusting of iron

• B. evaporation

• C. melting

• D. combustion

6. Particle size is a factor which affects reaction rates. Which statement(s) is/are NOT TRUE about particle size?

I. As the temperature rises, the molecules move faster and therefore collide more and have greater chances to react with each other.

II. The smaller pieces have a greater surface area, thus, providing much greater contact among the reactants and effecting more collisions. When solid reactants are present in small pieces, reaction rates increase.

III. As the temperature rises, the molecules move faster and therefore collide more and have greater chances to react with each other.

• A. I only

• B. I and III only

• C. II only

• D. I, II and III

7. How will crushing a solid into a powder increase the reaction rate?

• A. The activation energy barrier will be lowered.

• B. The orientation of colliding particles will be improved.

• C. The particles will collide with more energy.

• D. The powdered form has more surface area.

8. One of the factors that affect the rate of a chemical reaction is the concentration of the solution. Describe this factor.

• A. It is the measure of the number of particles of solute in a given volume of solution.

• B. It is located at the peak of the energy diagram for a reaction.

• C. It is the amount of energy needed for molecules to react.

• D. It is needed to break the bonds of the reactants to form new products or new substances.

9. To remove clothes stains faster, one either uses higher amounts of calamansi extract or laundry bleach. What factor influences this situation?

• A. concentration of the reactants

• B. size of the reactants

• C. presence of catalyst

• D. temperature

10. Perishable goods that are not properly stored show signs of spoilage in less than a day. Which of the following is NOT a possible cause of this spoilage?

• A. the amount of goods

• B. change in temperature

• C. oxygen in air

• D. presence of microorganisms