GCSE OCR Chemistry A Papers 2 and 4 Automarked

#1. 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?

Slow

Fast

#2. Why did the amount of oxygen in the atmosphere increase over time?

Oxygen was released during the Great Oxidation Period from extensive volcanic activity

Plants and other organisms began to perform photosynthesis, producing oxygen gas

Oxygen present in the Earth's mantle, seeped out over time and escaped via deep ocean ridges

#3. How did the oceans form?

Liquid water spontaneously formed when the ammonia and and methane in the atmosphere interacted chemically

Liquid water gradually seeped directly out of the Earths crust, for thousands of years

Water vapour in the atmosphere condensed as the Earth cooled, forming the oceans

#4. Which of these is a fast reaction?

Rusting

Explosions

Photosynthesis

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

No, even if there are still reactants

Yes, until reactants run out

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

Select all that apply:

distillation

filtration

reverse osmosis

#7. Why may our attempts to mitigate the effects of climate change cause further damage to the environment?

Animals and plants will resist the efforts we take to help them causing distress and loss of ecological productivity

Vulnerable ecosystems may be disrupted in our attempts to improve conditions for humans

Unexpected consequences often follow when we interrupt complex systems that do not fully understand e.g. the atmosphere

#8. What is the current composition of the Earth’s atmosphere?

78% carbon dioxide, 21% oxygen, 0.9% argon, and 0.1% other gases

78% nitrogen, 21% oxygen, 0.9% argon, and 0.1% other gases

78% oxygen, 21% nitrogen, 0.9% argon, and 0.1% other gases

#9. Which of the following examples matches the composition of Earth’s early atmosphere?

Mainly water vapour, some oxygen, little or no carbon dioxide and small amounts of other gases

Mainly oxygen, some water vapour, little or no carbon dioxide and small amounts of other gases

Mainly carbon dioxide, some water vapour, little or no oxygen and small amounts of other gases

#10. On the early Earth, there was a lot of volcanic activity as the planet was cooling down. How can we link this to the formation of the atmosphere?

Assume that volcanic activity is not relevant to the atmosphere and look for other sources of gases

Measure the gases released by volcanoes and compare them to the composition of the atmosphere over time

#11. 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 at higher temperatures move more quickly, collide more often and with enough energy to react

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

#12. Which geological process formed Earth’s atmosphere?

Glaciation

Volcanism

Continental drift

Earthquakes

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

unsaturation

desalination

demicronation

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

It will increase

It will decrease

It will stay the same

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

Rate of reaction is highest at very high and very low temperatures

As temperature increases, rate of reaction decreases

As temperature increases, rate of reaction increases

#16. Why do historical measurements by humans of global temperature have some uncertainty?

Select all that apply:

Instruments to measure temperature were not very accurate in the past and have gained more resolution over time

Early scientists were in competition to record the highest temperatures

The longest continuous record of temperature is only available in one place

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

Select all that apply:

By measuring the temperature throughout a reaction

By measuring the changes in volume of reactants and products

By measuring the changes in mass of reactants and products

By measuring the concentration of reactants and products throughout a reaction

#18. 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 slow changes require long-term experiments - costly and may exceed human lifetimes

Very small changes are difficult to accurately measure

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

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

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

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

#20. Which human activities cause increases in the greenhouse gases – carbon dioxide and methane?

Select all that apply:

Planting trees

Burning fossil fuels

Livestock farming

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

High energies cause spontaneous rearrangement of particles without impacts between them

High collision energies are more likely to break chemical bonds

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

No, even if reactants have not run out

Yes, until reactants run out

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

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

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

distilled water is cheaper than tap water

#24. What is the evidence supporting the idea that there was very little oxygen in the atmosphere in Earth’s early atmosphere?

Select all that apply:

The gravitational field strength of the Earth is not strong enough to hold oxygen in the atmosphere

No iron oxide bands in layers of rock are present in deeper (older) layers

Oxygen is not produced by volcanoes

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

Select all that apply:

chlorination

UV treatment

ozonation

alpha particle treatment

#26. Greenhouse effect 1) Fill in the blanks: Energy from the sun in the form of …….. hits the Earth’s surface and ……. are emitted back towards the atmosphere.

Visible/infrared waves, infrared waves

Sound waves, ocean waves

Gravitational waves, ultraviolet waves

#27. 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 --> filtration tower --> chlorine added --> water pumped to homes

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

#28. 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 concentration of the products of the reaction

The mass of the products of the reaction

The volume of the reactants of the reaction

The mass of the reactants of the reaction

The volume of the products of the reaction

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

It provides the activation energy needed

It removes excess nitrogen from the surrounding area, making ignition easier

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

#30. What evidence supports the notion that human activities are contributing to climate change?

Gradual climate warming has occurred since the evolution of our species

Correlation between increases in atmospheric temperatures and historic releases of greenhouse gases, due to combustion of fossil fuels

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

Yes

No

#32. Which of the following is the chemical test for oxygen?

Oxygen is bubbled through limewater and it turns cloudy when oxygen is present

An audible squeaky pop is heard when a lit splint is exposed to a test tube full of oxygen

A glowing splint is relit in a test tube filled with oxygen

#33. Which of the following are effects of climate change?

Select all that apply:

Extinctions of species unable to migrate or adapt to higher temperatures

Rising ocean temperatures causing coral bleaching and other adverse effects

Lower pH of oceans due to dissolving carbon dioxide producing carbonic acid

Rising sea levels due to ice in the south pole and in glaciers melting

More extreme weather events (stronger storms, rainfall and droughts)

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

No

Yes

Sometimes

#35. Why did the concentration of carbon dioxide in the atmosphere decrease after the oceans formed?

Carbon dioxide escaped the atmosphere as the Earth's spin increased in speed, causing an increase the centrifugal force

Carbon dioxide dissolved into the oceans and sea organisms used carbon in their shells as calcium carbonate

Carbon dioxide was split by photolysis, producing pure carbon which rained down as a solid.

#36. Which steps can we take to reduce the impact of climate change on humanity or prevent further climate change?

Select all that apply:

Using renewable energies instead of fossil fuels

Ensuring clean water supplies for vulnerable communities

Pumping water to the Sahara Desert and creating a new place to live

Building flood defences

Cutting down forests to give humans a new place to live

Carbon capture from the atmosphere and storage underground

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

Select all that apply:

rivers

lakes

aquifers

seawater

#38. Which evidence provides information about carbon dioxide concentration and global temperatures?

Ice cores which trap atmospheric gases when snow falls producing layers over time

Using the oldest continuous temperature measurements from humans and using computers to predict long term trends with this data

#39. Greenhouse effect 2) Fill in the blanks: Greenhouse gases such as ……….. , …………. and ……….. absorb infrared radiation from the Earth and re-emit it back to the Earth’s surface, causing warming.

Carbon dioxide, water vapour and nitrogen

Carbon dioxide, methane and water vapour

Carbon dioxide, oxygen and water vapour

#40. Which of these describes the term “rate of reaction”?

The rate of temperature change in the surroundings

The speed at which reactants are turned into products

The number of particles involved in a reaction in 1 minute

#41. 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?

The Introactive energy minimum

PR energy

Reactionary energy

Activation energy

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

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

When solutions are dilute, there are more particles in the same volume

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

GCSE OCR Chemistry A Papers 2 and 4

Good Luck!

Results

#1. 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?

#2. Why did the amount of oxygen in the atmosphere increase over time?

#3. How did the oceans form?

#4. Which of these is a fast reaction?

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

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

#7. Why may our attempts to mitigate the effects of climate change cause further damage to the environment?

#8. What is the current composition of the Earth’s atmosphere?

#9. Which of the following examples matches the composition of Earth’s early atmosphere?

#10. On the early Earth, there was a lot of volcanic activity as the planet was cooling down. How can we link this to the formation of the atmosphere?

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

#12. Which geological process formed Earth’s atmosphere?

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

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

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

#16. Why do historical measurements by humans of global temperature have some uncertainty?

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

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

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

#20. Which human activities cause increases in the greenhouse gases – carbon dioxide and methane?

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

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

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

#24. What is the evidence supporting the idea that there was very little oxygen in the atmosphere in Earth’s early atmosphere?

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

#26. Greenhouse effect 1) Fill in the blanks: Energy from the sun in the form of …….. hits the Earth’s surface and ……. are emitted back towards the atmosphere.

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

#28. 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?

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

#30. What evidence supports the notion that human activities are contributing to climate change?

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

#32. Which of the following is the chemical test for oxygen?

#33. Which of the following are effects of climate change?

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

#35. Why did the concentration of carbon dioxide in the atmosphere decrease after the oceans formed?

#36. Which steps can we take to reduce the impact of climate change on humanity or prevent further climate change?

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

#38. Which evidence provides information about carbon dioxide concentration and global temperatures?

#39. Greenhouse effect 2) Fill in the blanks: Greenhouse gases such as ……….. , …………. and ……….. absorb infrared radiation from the Earth and re-emit it back to the Earth’s surface, causing warming.

#40. Which of these describes the term “rate of reaction”?

#41. 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?

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

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