OCR Combined Science A Papers 4 and 10 Automock

#1. Why is there a minimum energy required for reactions to occur?

High collision energies are more likely to break chemical bonds

High energies cause spontaneous rearrangement of particles without impacts between them

#2. Iron is turned into iron oxide when exposed to the air. This is a process also known as rusting. Is the rate of reaction fast or slow in rusting?

Fast

Slow

#3. Temperature affects the rate of reaction. Which of the following is the correct description of what happens when temperature changes?

As temperature increases, rate of reaction increases

As temperature increases, rate of reaction decreases

#4. Surface area to volume ratio affects rate of reaction. Why is that the case?

With lower surface area to volume ratio, objects are much hotter and travel faster

With higher surface area to volume ratio, the overall temperature of reactants is lower, this leads to increased collision impact when struck

With higher surface area to volume ratio, there is more surface where collisions can take place

#5. Which of these is a fast reaction?

Explosions

Photosynthesis

Rusting

#6. When there are more frequent collisions between particles, what will happen to the rate of reaction?

It will decrease

It will stay the same

It will increase

#7. Chemical reactions require a high enough collision energy for reactions to take place. What do we call the minimum amount of energy needed for a reaction?

PR energy

The Introactive energy minimum

Activation energy

Reactionary energy

#8. Fresh water contains many different contaminants and so must be cleaned before it becomes potable. Which is the correct treatment path?

water from source --> sedimentation tank --> filtration tower --> chlorine added --> storage --> water pumped to homes

water from source --> chlorine added --> filtration tower --> sedimentation tank --> storage --> water pumped to homes

water from source --> filtration tower --> chlorine added --> water pumped to homes

#9. Why is a spark often needed to start a combustion reaction?

It releases electrons from their shells and they rapidly ignite the fuel

It provides the activation energy needed

#10. Is it possible to control the rate of reaction?

Yes

No

#11. Which of the following are the main sources of drinking water in the UK?

seawater

aquifers

rivers

lakes

#12. Which processes can we use for purifying sea water?

Select all that apply:

distillation

reverse osmosis

filtration

#13. In an experiment to measure the rate of photosynthesis of pondweed in a test tube, the number of bubbles (oxygen) produced per minute is used to determine the rate of reaction. What is this experiment actually measuring?

The volume of the reactants of the reaction

The volume of the products of the reaction

The mass of the reactants of the reaction

The concentration of the products of the reaction

The mass of the products of the reaction

#14. Does increasing the pressure of gases increase the rate of reaction?

Sometimes

Yes

No

#15. How could we accurately monitor the rate of a reaction? ? Three answers

Select all that apply:

By measuring the concentration of reactants and products throughout a reaction

By measuring the temperature throughout a reaction

By measuring the changes in mass of reactants and products

By measuring the changes in volume of reactants and products

#16. Which of the following are commonly used as methods of sterilising fresh water? ? 3

Select all that apply:

ozonation

UV treatment

chlorination

alpha particle treatment

#17. Why do we use distilled water for chemical analysis?

distilled water is cheaper than tap water

distilled water is warmer so it is better for conducting chemical analysis

tap water contains small amounts of dissolved salts which could contaminate the results

#18. Will exothermic reactions continue if there is no energy input?

Yes, until reactants run out

No, even if reactants have not run out

#19. Which of the following are problems that would arise from measuring an extremely slow rate of reaction?

Select all that apply:

Extremely slow reactions do not always follow the law of conservation of energy

Very small changes are difficult to accurately measure

Very slow changes require long-term experiments - costly and may exceed human lifetimes

#20. Which of these describes the term "rate of reaction"?

The number of particles involved in a reaction in 1 minute

The speed at which reactants are turned into products

The rate of temperature change in the surroundings

#21. Will endothermic reactions continue if there is no energy input?

Yes, until reactants run out

No, even if there are still reactants

#22. Increasing the concentration of solutions increases the rate of reaction, why is this the case?

More collisions take place because there are more particles in the same volume

When solutions are more concentrated, the intermolecular forces become weaker and bonds are more easily broken

#23. What is the name of the process by which salt is removed from water?

desalination

unsaturation

demicronation

#24. Which of these reasons explains why temperature affects rate of reaction?

Reactant particles at lower temperatures are struck by rapidly moving electrons, causing the reaction to happen faster

Reactant particles are unaffected by temperature, but the bonds at higher temperatures become weaker leading to an increased rate of reaction

Reactant particles at higher temperatures move more quickly, collide more often and with enough energy to react

GCSE OCR Combined Science A Papers 4 and 10

Good Luck!

Results

#1. Why is there a minimum energy required for reactions to occur?

#2. Iron is turned into iron oxide when exposed to the air. This is a process also known as rusting. Is the rate of reaction fast or slow in rusting?

#3. Temperature affects the rate of reaction. Which of the following is the correct description of what happens when temperature changes?

#4. Surface area to volume ratio affects rate of reaction. Why is that the case?

#5. Which of these is a fast reaction?

#6. When there are more frequent collisions between particles, what will happen to the rate of reaction?

#7. Chemical reactions require a high enough collision energy for reactions to take place. What do we call the minimum amount of energy needed for a reaction?

#8. Fresh water contains many different contaminants and so must be cleaned before it becomes potable. Which is the correct treatment path?

#9. Why is a spark often needed to start a combustion reaction?

#10. Is it possible to control the rate of reaction?

#11. Which of the following are the main sources of drinking water in the UK?

#12. Which processes can we use for purifying sea water?

#13. In an experiment to measure the rate of photosynthesis of pondweed in a test tube, the number of bubbles (oxygen) produced per minute is used to determine the rate of reaction. What is this experiment actually measuring?

#14. Does increasing the pressure of gases increase the rate of reaction?

#15. How could we accurately monitor the rate of a reaction? ? Three answers

#16. Which of the following are commonly used as methods of sterilising fresh water? ? 3

#17. Why do we use distilled water for chemical analysis?

#18. Will exothermic reactions continue if there is no energy input?

#19. Which of the following are problems that would arise from measuring an extremely slow rate of reaction?

#20. Which of these describes the term "rate of reaction"?

#21. Will endothermic reactions continue if there is no energy input?

#22. Increasing the concentration of solutions increases the rate of reaction, why is this the case?

#23. What is the name of the process by which salt is removed from water?

#24. Which of these reasons explains why temperature affects rate of reaction?

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