Understanding Reaction Rates and Equilibrium

Which of the following best describes the collision theory of chemical reactions?

• Particles must collide with sufficient energy and proper orientation to react.

• All collisions between particles result in a chemical reaction.

• Reactions only occur when particles are in a gaseous state.

• The rate of reaction is independent of temperature.

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NGSS.HS-PS1-5

Which factor will increase the rate of a chemical reaction according to collision theory?

• Decreasing the concentration of reactants

• Lowering the temperature

• Increasing the surface area of a solid reactant

• Removing a catalyst

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NGSS.HS-PS1-5

What does the peak of a potential energy diagram for a chemical reaction represent?

• The energy of the reactants

• The activation energy

• The energy of the products

• The equilibrium position

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NGSS.HS-PS1-4

Which statement best describes chemical equilibrium?

• The reactants are completely converted to products.

• The concentrations of reactants and products are equal.

• The rates of the forward and reverse reactions are equal.

• The reaction stops completely.

According to Le Chatelier's Principle, what will happen if the concentration of a reactant is increased in a system at equilibrium?

• The system will shift to produce more products.

• The system will shift to produce more reactants.

• The equilibrium will not be affected.

• The temperature of the system will increase.

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NGSS.HS-PS1-5

Which of the following changes will NOT affect the rate of a chemical reaction?

• Changing the temperature

• Changing the pressure (for gases)

• Changing the color of the container

• Adding a catalyst

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NGSS.HS-PS1-5

If a reaction is exothermic, how does the potential energy of the products compare to the reactants?

• Products have higher potential energy than reactants.

• Products have lower potential energy than reactants.

• Products and reactants have the same potential energy.

• Cannot be determined.

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NGSS.HS-PS1-4

Which of the following will decrease the rate of a reaction?

• Increasing temperature

• Decreasing concentration of reactants

• Adding a catalyst

• Increasing surface area

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NGSS.HS-PS1-5

Which of the following is a correct representation of a reversible reaction at equilibrium?

Which of the following best explains why increasing temperature generally increases the rate of a chemical reaction?

• It increases the number of collisions with sufficient energy.

• It decreases the activation energy.

• It increases the mass of the reactants.

• It changes the products formed.

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NGSS.HS-PS1-5