Chemistry Paper 2
Studied by 0 people
Call with Kai
Learn
Practice Test
Spaced Repetition
Match
Flashcards
Knowt Play1/70
There's no tags or description
Looks like no tags are added yet.
Name | Mastery | Learn | Test | Matching | Spaced | Call with Kai |
|---|
No study sessions yet.
71 Terms
What factors affect the rate of reaction?
Temperature, concentration (or pressure), surface area, catalyst.
Why does increasing temperature increase rate of reaction?
Particles have more kinetic energy so collide more often and with more energy.
What is activation energy?
The minimum energy needed for a successful collision.
How does concentration affect rate of reaction?
Higher concentration means more particles per volume so more frequent collisions.
How does pressure affect rate in gases?
Higher pressure forces particles closer together increasing collision frequency.
Why does increasing surface area increase reaction rate?
More particles are exposed leading to more collisions.
What does a catalyst do in a reaction?
It lowers activation energy by providing an alternative pathway.
Is a catalyst used up during a reaction?
No, it remains chemically unchanged.
What is a reversible reaction?
A reaction that can go forwards and backwards.
What does equilibrium mean?
Forward and backward reactions occur at the same rate.
How does temperature affect equilibrium position?
Increasing temperature favours the endothermic direction.
How does pressure affect equilibrium position?
Equilibrium shifts to the side with fewer gas molecules.
How does concentration affect equilibrium position?
Equilibrium shifts to oppose the change made.
Does a catalyst change the equilibrium position?
No, it only helps equilibrium be reached faster.
Why is the Haber Process a common 6 marker?
It involves rate, equilibrium, temperature, pressure and catalysts.
What test identifies hydrogen gas?
A lit splint produces a squeaky pop.
What test identifies oxygen gas?
A glowing splint relights.
What test identifies carbon dioxide gas?
Limewater turns cloudy.
How do you test for chlorine gas?
It bleaches damp blue litmus paper white.
What colour flame does sodium produce?
Yellow.
What colour flame does potassium produce?
Lilac.
What colour flame does copper produce?
Green.
What reagent tests for chloride ions?
Silver nitrate producing a white precipitate.
What reagent tests for sulfate ions?
Barium chloride producing a white precipitate.
How do you test for carbonate ions?
Add acid and test for carbon dioxide.
What is chromatography used for?
Separating and identifying substances.
Why do substances separate in chromatography?
Different solubilities and attractions to the paper.
What does an Rf value show?
Distance moved by substance divided by distance moved by solvent.
Why must pencil be used in chromatography?
Pen ink dissolves and affects results.
Why is chromatography a frequent 6 marker?
It includes method, explanation, calculation and evaluation.
What is the main gas in Earth’s atmosphere?
Nitrogen.
What percentage of the atmosphere is oxygen?
About 21%.
How was the early atmosphere formed?
From gases released by volcanoes.
Why did carbon dioxide levels decrease over time?
It dissolved in oceans and was used in photosynthesis.
Why did oxygen levels increase?
Photosynthesis by algae and plants.
What are greenhouse gases?
Gases that trap heat in the atmosphere.
Name two greenhouse gases.
Carbon dioxide and methane.
How do humans increase carbon dioxide levels?
Burning fossil fuels and deforestation.
Why does deforestation increase carbon dioxide levels?
Less photosynthesis removes less carbon dioxide.
What is global warming?
The increase in Earth’s average temperature.
Why is climate change a common 6 marker?
It links chemistry, data interpretation and evaluation.
What is a finite resource?
A resource that will eventually run out.
Name three fossil fuels.
Coal, oil and natural gas.
Why are fossil fuels non-renewable?
They take millions of years to form.
What are renewable resources?
Resources that can be replaced naturally.
Name three renewable energy sources.
Solar, wind and hydroelectric.
Give one advantage of renewable energy.
It produces little or no pollution.
Give one disadvantage of renewable energy.
It can be unreliable or expensive to set up.
What is potable water?
Water that is safe to drink.
How is potable water produced?
Filtration, sterilisation or distillation.
Why is desalination expensive?
It requires large amounts of energy.
Why is water treatment a common 6 marker?
It involves methods and evaluation.
Why is recycling important?
It conserves resources and reduces landfill.
What is life cycle assessment (LCA)?
Assessing environmental impact of a product.
What are the four stages of LCA?
Raw materials, manufacture, use and disposal.
Why do LCAs involve judgement?
Data may be incomplete or subjective.
What is corrosion?
The destruction of materials by chemical reactions.
What is rusting?
The corrosion of iron involving oxygen and water.
How can rusting be prevented?
Painting, oiling, galvanising or sacrificial protection.
What is sacrificial protection?
Using a more reactive metal to protect iron.
Why is LCA a frequent 6 marker?
It requires explanation, comparison and evaluation.
What is a hypothesis?
A testable scientific prediction.
What is a control variable?
A variable kept the same in an experiment.
What is accuracy?
How close a result is to the true value.
What is precision?
How close repeated results are to each other.
Why are repeat readings important?
To identify anomalies and improve reliability.
What is an anomaly?
A result that does not fit the pattern.
Why is peer review important?
It checks the validity of scientific research.
How can reliability be improved?
By repeating experiments and increasing sample size.
Why are evaluation questions common in chemistry?
They test understanding of scientific method.