GCSE Combined Science (Chemistry -
Paper 2)
Describe four potential effects of global climate change. - correct answerIce caps
melting, resulting in flooding due to raised sea levels. Increase in extreme weather,
resulting in droughts and floods. Species in some areas may become extinct. Warming
climates can result in mosquitos migrating, resulting in malaria travelling to countries
that were not affected before.
Describe some ways carbon dioxide emissions can be reduced. - correct
answerProducing electricity using renewable resources, Planting trees when others are
felled, using public transport/walking/cycling, carbon capture at source
Describe some ways methane emissions can be reduced. - correct answerEating less
meat/becoming vegetarian, maintain natural gas pipes to stop leaks
Describe the greenhouse effect. - correct answerShort wavelength radiation passes
through atmosphere and absorbed by Earth's surface, which heats up. This releases
long wavelength radiation (Infra Red), which is absorbed by greenhouse gases and
reflected back to Earth, heating it up.
Explain why an increase in concentration increases the reaction rate - correct
answerParticle are more CROWDED, so the collisions are more FREQUENT
Explain why an increase in surface area increases the reaction rate. - correct
answerParticles are more EXPOSED, so collisions are more FREQUENT
Explain why an increase in temperature increases the rate of reaction - correct
answerParticles move FASTER, so collisions are more FREQUENT and more
FORCEFUL
Give two examples of natural products that have been replaced by man-made ones. -
correct answerCotton replaced by Nylon in clothes, Window frames made of wood now
made of plastic (uPVC)
How are fossil fuels formed? - correct answerThe decomposition of dead plants and
animals WITHOUT OXYGEN PRESENT.
How are oxides of nitrogen formed when burning fuels? - correct answerHigh
temperatures in car engines make nitrogen and oxygen react together
How are substances separated using chromatography? - correct answerDifferent
substances have different attractions to the stationary phase and different solubilities in
the mobile phase.
, How can copper be obtained from copper compounds? - correct answerDisplacement
by using scrap iron OR by electrolysis
How can people reduce the use of limited resources and the environmental impact? -
correct answerreduce the use of some resources, reuse resources, recycle resources
How can sea water be desalinated? - correct answerDistillation
How can you calculate mean rate of reaction? - correct answerAmount of product made
/ time taken
How can you test to see if you have a pure substance? - correct answerPure
substances melt and boil at specific temperatures. To test you can find the melting point
of the substance and compare it to what it should be if pure.
How can you use chromatography to test whether a substance is pure? - correct
answerA pure substance will produce one spot.
How did the oxygen in today's atmosphere build up? - correct answerPlants evolved
and produced it through photosynthesis
How do you calculate the Rf value? - correct answerDistance moved by the substance /
Distance moved by the solvent
How does a catalyst increase reaction rate? - correct answerIt provides a different route
for the reaction that has a lower activation energy
How does a change in pressure affect a reaction at equilibrium? - correct answerAn
increase in pressure shifts the equilibrium to the side with less moles of gas. A decrease
in pressure shifts equilibrium to the side with more moles of gas.
How does the flammability of a hydrocarbon change with size? - correct answerThe
bigger the hydrocarbon the harder it is to catch fire
How does the size of a hydrocarbon affect the boiling point? - correct answerThe bigger
the hydrocarbon the higher the boiling point
How does the viscosity of a hydrocarbon change with size? - correct answerThe bigger
the hydrocarbon the more viscous they are
How is a fractional distillation column designed to allow hydrocarbons to be separated?
- correct answerIt has a temperature gradient (hot at the bottom, cold at the top)
How is a high concentration different to a low concentration? - correct answerThere are
more particles in a given volume at a high concentration
Paper 2)
Describe four potential effects of global climate change. - correct answerIce caps
melting, resulting in flooding due to raised sea levels. Increase in extreme weather,
resulting in droughts and floods. Species in some areas may become extinct. Warming
climates can result in mosquitos migrating, resulting in malaria travelling to countries
that were not affected before.
Describe some ways carbon dioxide emissions can be reduced. - correct
answerProducing electricity using renewable resources, Planting trees when others are
felled, using public transport/walking/cycling, carbon capture at source
Describe some ways methane emissions can be reduced. - correct answerEating less
meat/becoming vegetarian, maintain natural gas pipes to stop leaks
Describe the greenhouse effect. - correct answerShort wavelength radiation passes
through atmosphere and absorbed by Earth's surface, which heats up. This releases
long wavelength radiation (Infra Red), which is absorbed by greenhouse gases and
reflected back to Earth, heating it up.
Explain why an increase in concentration increases the reaction rate - correct
answerParticle are more CROWDED, so the collisions are more FREQUENT
Explain why an increase in surface area increases the reaction rate. - correct
answerParticles are more EXPOSED, so collisions are more FREQUENT
Explain why an increase in temperature increases the rate of reaction - correct
answerParticles move FASTER, so collisions are more FREQUENT and more
FORCEFUL
Give two examples of natural products that have been replaced by man-made ones. -
correct answerCotton replaced by Nylon in clothes, Window frames made of wood now
made of plastic (uPVC)
How are fossil fuels formed? - correct answerThe decomposition of dead plants and
animals WITHOUT OXYGEN PRESENT.
How are oxides of nitrogen formed when burning fuels? - correct answerHigh
temperatures in car engines make nitrogen and oxygen react together
How are substances separated using chromatography? - correct answerDifferent
substances have different attractions to the stationary phase and different solubilities in
the mobile phase.
, How can copper be obtained from copper compounds? - correct answerDisplacement
by using scrap iron OR by electrolysis
How can people reduce the use of limited resources and the environmental impact? -
correct answerreduce the use of some resources, reuse resources, recycle resources
How can sea water be desalinated? - correct answerDistillation
How can you calculate mean rate of reaction? - correct answerAmount of product made
/ time taken
How can you test to see if you have a pure substance? - correct answerPure
substances melt and boil at specific temperatures. To test you can find the melting point
of the substance and compare it to what it should be if pure.
How can you use chromatography to test whether a substance is pure? - correct
answerA pure substance will produce one spot.
How did the oxygen in today's atmosphere build up? - correct answerPlants evolved
and produced it through photosynthesis
How do you calculate the Rf value? - correct answerDistance moved by the substance /
Distance moved by the solvent
How does a catalyst increase reaction rate? - correct answerIt provides a different route
for the reaction that has a lower activation energy
How does a change in pressure affect a reaction at equilibrium? - correct answerAn
increase in pressure shifts the equilibrium to the side with less moles of gas. A decrease
in pressure shifts equilibrium to the side with more moles of gas.
How does the flammability of a hydrocarbon change with size? - correct answerThe
bigger the hydrocarbon the harder it is to catch fire
How does the size of a hydrocarbon affect the boiling point? - correct answerThe bigger
the hydrocarbon the higher the boiling point
How does the viscosity of a hydrocarbon change with size? - correct answerThe bigger
the hydrocarbon the more viscous they are
How is a fractional distillation column designed to allow hydrocarbons to be separated?
- correct answerIt has a temperature gradient (hot at the bottom, cold at the top)
How is a high concentration different to a low concentration? - correct answerThere are
more particles in a given volume at a high concentration
