Starter quiz
- When magnesium reacts with acid, hydrogen gas is produced which we can collect in a test tube. To test if it is hydrogen, we hold a burning splint to the test tube and hear a ______.
- 'squeaky pop' ✓
- Some metals, like gold and platinum, are found in their native state in nature, and nothing much happens when other chemicals are added. We call these metals very ______.
- 'unreactive' ✓
- The higher the position of a metal in the reactivity series, the more ______ it is likely to react.
- 'vigorously' ✓
- The thermite reaction needs a bit of input of energy before it starts, but then releases energy and is so ______ that it can weld railway lines.
- 'exothermic' ✓
- Some reactions are slow, whereas other reactions are much faster. Hydrogen and oxygen do not react with each other spontaneously. What would it need to make them react?
- a higher concentration of both gases
- energy, for example heat or a flame ✓
- mixing the gases together
- putting the gases in water
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- Metal A is more reactive than metal B. What type of reaction would take place if metal A is added to a solution of a salt of metal B?
- a combustion reaction
- a decomposition reaction
- a displacement reaction ✓
- a neutralisation reaction
- an oxidation reaction
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Exit quiz
- Some substances simply do not react with each other, e.g. platinum and water. In others you can see a spontaneous reaction but it is very slow: e.g. ______ of hydrogen peroxide to water and oxygen.
- 'decomposition' ✓
- Metals and metal salts are good catalysts. This is not just because there are so many metals. They have specific characteristics, or ______, that make them so suitable as catalysts.
- 'properties' ✓
- A catalytic converter efficiently converts unwanted combustion products (e.g. CO, C, NOx) into CO and N. Why are these two gases preferred over the other substances?
- CO, C and NOx are climate pollutants. ✓
- CO, C and NOx are toxic to the environment, including humans. ✓
- CO is harmless
- N came from the air anyway. ✓
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- Why do living cells bother changing hydrogen peroxide to water and oxygen, and why do they use a catalyst?
- HO is harmful (and HO and O are not). ✓
- Living cells can use the catalyst for other reactions too.
- The spontaneous reaction is far too slow. ✓
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- Match the following key terms to their definition.
- catalyst⇔a chemical that speeds up rate of a reaction without being used up ✓
- chemical reaction⇔when atoms are rearranged, and changes can be observed e.g. bubbles ✓
- decomposition reaction⇔type of reaction when a reactant breaks down into two or more products ✓
- enzyme⇔a biological catalyst that speeds up reactions in living things ✓
- Why is the lock and key model a good model of an enzyme?
- Only the correctly shaped key will open the lock. ✓
- Only the correctly shaped substrate will fit the active site. ✓
- The keyhole represents the active site. ✓
- The lock can be used many times and so can the enzyme. ✓
- The lock represents the enzyme; the key represents the substrate. ✓
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Worksheet
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Presentation
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Video
Lesson Details
Key learning points
- A catalyst speeds up a chemical reaction without being used up or chemically changed.
- Catalysts are specific to particular reactions; different reactions require different catalysts.
- Enzymes are biological catalysts that speed up reactions in living cells.
Common misconception
The catalyst is one of the reactants and gets used up during the reaction.
Emphasise that the chemical reaction will take place without the catalyst but at a very slow rate.
Keywords
Catalyst - a chemical that speeds up the rate of a reaction without itself being used up
Enzyme - a biological catalyst that speeds up reactions in living things
Chemical reaction - when atoms are rearranged to make new products and changes can be observed e.g. bubbles of gas forming
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