Understanding Reaction Rates in Chemistry

Which of the following is a factor that affects reaction rates?

• Color of the reactants

• Temperature

• Shape of the container

• Time of day

Tags

NGSS.HS-PS1-5

According to collision theory, what must happen for a reaction to occur?

• Reactants must be in a gaseous state

• Reactants must collide with sufficient energy and proper orientation

• Reactants must be dissolved in water

• Reactants must be at room temperature

What is the role of a catalyst in a chemical reaction?

• It increases the temperature of the reaction

• It lowers the activation energy required for the reaction

• It changes the products of the reaction

• It increases the concentration of reactants

How does increasing the temperature generally affect the rate of a chemical reaction?

• It decreases the reaction rate

• It has no effect on the reaction rate

• It increases the reaction rate

• It changes the reaction mechanism

Tags

NGSS.HS-PS1-5

Which of the following statements best describes the effect of concentration on reaction speed?

• Higher concentration of reactants generally decreases the reaction speed

• Higher concentration of reactants generally increases the reaction speed

• Concentration has no effect on reaction speed

• Higher concentration of products increases the reaction speed

Tags

NGSS.HS-PS1-5

Explain why increasing the surface area of a solid reactant increases the reaction rate.

• It allows more reactant particles to collide per unit time

• It increases the temperature of the reaction

• It changes the chemical properties of the reactant

• It decreases the activation energy

Tags

NGSS.HS-PS1-5

Describe how a catalyst affects the energy profile of a reaction.

• It raises the energy of the reactants

• It lowers the activation energy peak

• It increases the energy of the products

• It has no effect on the energy profile

Using collision theory, explain why increasing temperature increases reaction rates.

• Higher temperature increases the number of collisions with sufficient energy

• Higher temperature decreases the number of collisions

• Higher temperature changes the orientation of molecules

• Higher temperature decreases the energy of collisions

Tags

NGSS.HS-PS1-5

Predict the effect of decreasing the concentration of a reactant on the rate of reaction, and explain your reasoning.

• The rate increases because there are fewer particles

• The rate decreases because there are fewer collisions

• The rate remains unchanged because concentration does not affect rate

• The rate increases because the activation energy is lower

Tags

NGSS.HS-PS1-5

A reaction is found to proceed faster when a catalyst is added. Explain how the catalyst achieves this without being consumed in the reaction.

• It provides an alternative pathway with lower activation energy

• It increases the concentration of reactants

• It raises the temperature of the reaction

• It changes the products of the reaction

Tags

NGSS.HS-PS1-5