Student:______
Class:______
Teacher:______
Useful and harmful reactions Due date: ______
Some chemical reactions are listed below.
Task: Draw up a table with the headings ‘helpful’ and ‘harmful’ and write each reaction in the correct column with your reasons for putting it there.
Chemical reactions:
1. You burn natural gas in a boiler.
2. Parts of a car start to go rusty.
3. You cook some chips in the oven.
4. Petrol is used in a car engine.
5. Petrol used in a car engine gives off exhaust fumes.
6. You use a ‘catalytic converter’ to reduce the pollution from car exhausts.
7. Acid rain corrodes a limestone building.
8. Chemicals in an anti-spot cream react with a silver necklace, turning it black.
9. ‘Perming lotion’ is used to make hair curlier or straighter.
10. Ozone in the upper atmosphere absorbs ultra-violet rays and changes into normal oxygen.
Past-paper questions Due date: ______
1 (level 4) The diagram shows a key which can be used to identify different chemicals.
(a) Use the key to identify chemicals A, B and C.
(i) Chemical A is a white powder. It fizzes when dilute hydrochloric acid is added. It dissolves in cold water.
Chemical A is ......
1 mark
(ii) Chemical B is a green powder. It does not fizz when dilute hydrochloric acid isadded
Chemical B is ......
1 mark
(iii) Chemical C is a white powder. It does not fizz when dilute hydrochloric acid is added. It is insoluble in cold water.
Chemical C is ......
1 mark
(b) Nickel carbonate is green. It is the nickel that makes nickel carbonate green, not the carbonate. Explain, using information from the key, how you know that this is true.
......
......
......
......
2 marks
Maximum 5 marks
2 (level 4) Dilute acids react with many things.
Tick the four boxes by the correct descriptions.
Tick no more than four boxes.
Acids always dissolve glass.
Acids can be burned as fuels.
Acids damage teeth.
Acids react with metals such as magnesium.
Acids turn universal indicator solution blue.
Acids may harm your skin.
Acids react with limestone.
Acids are always poisonous.
4 marks
3 (level 4). Some chemical reactions change raw materials into useful substances.
(a) Draw lines to connect each raw material to the substance produced from it.
raw substance
material produced
clay • • glass
ore • • metal
sand • • pottery
wood • • paper
4 marks
(b) Listed below are five changes.
Tick the boxes by the two chemical changes.
making yoghurt from milk
boiling water in an electric kettle
burning petrol in a car engine
diluting orange juice with water
making aluminium cans from a block of aluminium metal
2 marks
Maximum 6 marks
4(level 5). Indra collects samples of three gases.
She carries out the following tests.
1. She adds a few drops of limewater to one test tube of each gas and shakes it.
2. She puts a burning splint (spill) into the other test tube of each gas.
Complete each box in the table below to describe the results of her tests.
If there is no effect, write ‘no effect’.
limewater / effect of putting a burning
splint into the gas
carbon
dioxide
oxygen
hydrogen
Maximum 6 marks
Reactions wordsearch Due date: ______
Solve the clues below, then find the answers in the wordsearch grid.
1 The product of the reaction between copper and oxygen. ______
2 The name given to chemicals which react together. ______
3 This is released when fuels burn in oxygen. ______
4 The metal which reacts with oxygen to form magnesium oxide. ______
5 The name given to new chemicals which are made in a reaction. ______
6 When a fuel burns, this gas is produced. (It contains carbon.) ______
7 The other chemical produced when a fuel burns. ______
8 The oxide formed when zinc reacts with oxygen. ______
9 Combustion reactions cannot be reversed. They are ______
10 This metal forms a black oxide when it is heated. ______
C / A / R / B / O / N / D / I / O / X / I / D / EW / B / E / D / S / U / L / P / S / R / R / E / O
A / Z / A / B / A / C / O / P / P / E / R / O / Z
T / D / C / I / R / F / T / K / U / D / E / G / I
E / F / T / K / O / O / L / T / B / O / V / H / N
R / M / A / G / N / E / S / I / U / M / E / L / C
A / W / N / E / M / E / T / J / W / S / R / E / O
X / R / T / P / R / O / D / U / C / T / S / C / X
O / F / S / U / Q / E / G / U / E / A / I / A / I
Z / E / W / L / O / N / S / O / C / C / B / Q / D
D / A / E / T / N / E / H / E / Q / Y / L / V / E
C / O / P / P / E / R / O / X / I / D / E / J / T
D / A / Y / S / R / G / L / Y / T / E / A / I / D
C / H / I / R / A / Y / A / B / U / Q / S / L / F
Name:______
Topic: Chemical Reactions
Homework / TestUseful and harmful reactions / Past-paper questions / Reactions wordsearch / Percentage / Level
Target for next module:
______
Key words:
Physical Carbon dioxide
Chemical Combustion
Reversible Oxides
Oxygen metals
Hydrogen Reactants
Products Carbonates
Acids energy
What you need to know:
1. How to test for Oxygen, Carbon dioxide and Hydrogen (level 3)
2. Name the gases released when acids react with metals and carbonates (level 5)
3. To understand the difference between physical and chemical changes (level 4)
4. Recognise that the total mass of reactants is always equal to the total mass of products (level 5)
5. To know that oxygen is needed for substances to burn (level 4)
6. Represent chemical reactions as word equations (level 5)