Factors affecting rates of reactions

What is required for a reaction to occur between particles?

• Particles must collide with high speed

• Particles must collide with a minimum amount of energy

• Particles must be in a gaseous state

• Particles must be of the same type

How does increasing temperature affect the rate of reaction?

• It increases the frequency of successful collisions

• It decreases the energy of the particles

• It makes particles collide less frequently

• It reduces the number of particles available

What happens when the concentration of reactants is increased?

• The reaction slows down

• The number of successful collisions decreases

• The reaction becomes faster

• The particles become less reactive

How does changing pressure affect reactions involving gases?

• It has no effect on the reaction rate

• It slows down the reaction

• It speeds up the reaction

• It only affects solid reactants

What is the effect of surface area on the rate of reaction?

• More finely divided solids react faster

• Smaller surface area increases the reaction rate

• Surface area has no effect on reactions

• Larger surface area slows down the reaction

What is a catalyst?

• A substance that increases the activation energy

• A substance that decreases the temperature of a reaction

• A substance that speeds up a reaction without being used up

• A substance that is consumed in a reaction

How do catalysts work?

• By increasing the activation energy

• By providing an alternative route with lower activation energy

• By consuming reactants

• By changing the temperature of the reaction

What happens to the energy of particles when a catalyst is used?

• The energy of the particles increases

• The energy of the particles decreases

• The energy of the particles becomes unpredictable

• The energy of the particles remains unchanged

What is activation energy?

• The minimum energy needed for a reaction to occur

• The energy required to break bonds

• The energy that particles lose during a collision

• The energy released during a reaction

Why do reactions between solids and liquids occur faster with smaller solid pieces?

• Smaller pieces collide less frequently

• Smaller pieces have less surface area

• Smaller pieces are less reactive

• Smaller pieces have more surface area exposed