Revision work for chemistry Grade-7 2021.
Revision work for chemistry Grade-7 2021.
Chose the best.
1. A hydrocarbon is a compound containing only hydrogen and ----------------------.
A. Sodium
B. Carbon
C. Chlorine
D. All
2. Fossil fuels are called --------------------------fuels.
A. Renewable
B. Non-renewable
C. Both
D. None of them
3. In an oil refinery the --------------------- oil is separated into its fractions.
A. Olive
B. Seed
C. Crude
D. None of them
4. Unsaturated compounds turn ----------------------------- bromine water colourless.
A. Red
B. Blue
C. Black
D. Yellow
5. The ------------------------------ have at least one double bond between carbon atoms.
A. Alkanes
B. Alkenes
C. Alkynes
D. All
True and False
1. Most of our common fuels are fossil fuels. T
2. Ethene and the other alkenes are called saturated compounds. F
3. When we burn a fuel, the reaction is called combustion. T
4. Petrol is a mixture of hydrocarbons. T
5. When hydrocarbons burn, they are reduced. F
6. Carbon dioxide is given off from car exhausts. F
7. Burning fossil fuels causes acid rain. T
8. The Earth's atmosphere acts like a greenhouse. T
Fill in the blanks.
1. A hydrocarbon is a compound containing only hydrogen and -----------. carbon
2. Most of our common fuels are ---------------. fossil fuels
3. Fossil fuels are called --------------- fuels. non-renewable
4. In an oil refinery the crude oil is separated into its ------------------------. fractions
5. Remember that a fraction is a group of hydrocarbons with similar ----------------------- points. boiling
6. Cracking is when we break down large ----------------- into smaller, more useful ones. Hydrocarbons
7. The -------------------- have at least one double bond between carbon atoms. Alkenes
8. Ethene and the other alkenes are called -------------- compounds. Unsaturated
9. Unsaturated compounds turn ---------------------- bromine water colorless. Yellow
10. When we burn a fuel, the reaction is called ---------------. combustion
11. Petrol is a ----------------------- of hydrocarbons. Mixture
12. When hydrocarbons burn, they are -------------.
oxidized13. Carbon --------------------- is given off from car exhausts. Monoxide
14. Burning fossil fuels causes ---------------------. acid rain
15. Most petrol is -------------------free now. Sulfur
16. The Earth's atmosphere acts like a -----------------. greenhouse
17. plants absorb --------------------- gas. carbon dioxide
Thank Sr
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