HS-PS1-5: Factors Affecting Reaction Rates

Which factor increases the rate of a chemical reaction by lowering the activation energy?

• Temperature

• Concentration

• Catalyst

• Surface area

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

• It decreases the reaction rate

• It increases the reaction rate

• It has no effect

• It slows down the formation of products

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Which of the following explains why an increase in temperature speeds up a reaction?

• Molecules move slower and collide less often

• There is a decrease in activation energy

• Particles move faster and collide more frequently

• The reactants change into different products

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NGSS.HS-PS1-5

Why does increasing the concentration of reactants generally speed up a reaction?

• It increases the frequency of collisions between molecules

• It lowers the activation energy

• It changes the products formed

• It absorbs more energy

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NGSS.HS-PS1-5

A student grinds a solid reactant into a fine powder before reacting it with a liquid. How will this affect the reaction rate?

• The reaction rate will decrease

• The reaction rate will increase

• The reaction will stop completely

• The reaction rate will remain unchanged

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NGSS.HS-PS1-5

Which of the following best explains why a catalyst speeds up a reaction?

• It increases the energy of the reactants

• It lowers the activation energy required for the reaction

• It decreases the number of successful collisions

• It makes the reaction irreversible

Which of the following changes would likely decrease the rate of a chemical reaction?

• Increasing the temperature

• Increasing the concentration of reactants

• Adding a catalyst

• Decreasing the surface area of a solid reactant

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Why does increasing the surface area of a reactant speed up a chemical reaction?

• It increases the number of effective collisions

• It decreases the activation energy

• It absorbs more heat

• It prevents the reaction from occurring

Which statement correctly describes the role of a catalyst in a chemical reaction?

• A catalyst is consumed in the reaction

• A catalyst decreases the amount of product formed

• A catalyst lowers the activation energy and remains unchanged

• A catalyst increases the activation energy

In a reaction between a solid and a liquid, which of the following would result in the FASTEST reaction rate?

• Using a large solid chunk

• Using powdered solid

• Decreasing the temperature

• Using a diluted solution

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NGSS.HS-PS1-5