19.4: Reaction Rates

Which of the following is an example of a rapid chemical reaction?

• Rusting of steel

• Dissolving sugar in water

• Combustion of rocket fuel

• Spoiling of milk

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Which reaction occurs so slowly that changes may not be noticed right away?

• Combustion of gasoline

• Rusting of steel

• Explosion of grain dust

• Burning of magnesium

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What is the reaction rate?

• The total energy released in a reaction

• The mass of products formed

• The speed at which reactants change into products

• The temperature of the reaction

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Which of the following could a chemist use to describe a reaction rate?

• How fast a reactant is used up

• How fast a product is formed

• How fast energy is released

• All of the above

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Why must a chemist state the conditions under which a reaction occurs?

• Reaction rates are always the same

• Reaction rates depend on conditions

• Products change based on conditions

• Reactants disappear under conditions

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Which idea explains why changing conditions affects reaction rates?

• Law of conservation of mass

• Periodic law

• Collision model

• Atomic theory

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

• Particles must dissolve

• Particles must heat up

• Particles must collide

• Particles must evaporate

Why does increasing temperature usually increase reaction rate?

• Particles become heavier

• Particles move slower

• Particles collide more often and with more energy

• Particles stop reacting

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What does concentration describe?

• Temperature of a solution

• Volume of a container

• Number of particles per unit volume

• Speed of particle movement

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Why does magnesium react faster in more concentrated hydrochloric acid?

• The acid is hotter

• There are more reacting particles

• The magnesium is smaller

• The product forms bubbles

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