U3AoS2: Rates of Reactions

The following changes are made to a reaction mixture. Which change will lead to a decrease in reaction rate?

• Smaller solid particles are used

• A catalyst is added

• Increase in concentration of aqueous reactants

• Decrease in temperature

Tags

NGSS.HS-PS1-5

What was our independent variable in the iodine clock demonstration?

• sulfuric acid

• potassium iodide

• sodium thiosulfate

• hydrogen peroxide

What was consumed in the demonstration for the iodine clock to make it appear black?

• iodine

• iodide

• thiosulfate

• peroxide

Which pair of statements is correct for the effects

• Option A

• Option B

• Option C

• Option D

Tags

NGSS.HS-PS1-5

Which statement correctly describes what must occur when reactant particules collide and react?

• Colliding particles must have equal amounts of kinetic energy

• Colliding particles must have different amounts of kinetic energy

• Colliding particles must have kinetic energy greater than or equal to the activation energy of the reaction.

• Colliding particles must have kinetic energy greater than or equal to the average kinetic energy

A catalyst...

• slows the rate of reaction

• has no effect on the rate of reaction.

• ensures that a reaction is exothermic

• provides an alternative pathway for the reaction with a lower activation energy

Tags

NGSS.HS-PS1-5

Which of the following statements is true?

• Catalysts decrease the difference in enthalpy between reactants and products

• Catalysts are gradually used up in a reaction.

• Catalysts increase the proportion of particles with sufficient energy to react.

• Catalysts increase the yield of a reaction.

Tags

NGSS.HS-PS1-5

In the diagram shown, one collision is successful, but the other is not. Which of the following factors explains the success of the first reaction?

• Temperature

• Concentration

• Orientation

• Catalysis

Tags

NGSS.HS-PS1-5