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Chemistry in daily life
22 Government jobs Everyday science questions with answers and explanations.
Printable worksheet with answer key
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The chemical formula of common salt is:
- 1 CaCl₂
- 2 Na₂CO₃
- 3 NaCl
- 4 KCl
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The gas that makes up most of the Earth's atmosphere is:
- 1 Carbon dioxide
- 2 Oxygen
- 3 Nitrogen
- 4 Argon
Show answer
Correct answer: Nitrogen
Nitrogen is about 78 percent of dry air. Oxygen is about 21 percent.
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Vinegar contains:
- 1 Lactic acid
- 2 Formic acid
- 3 Acetic acid
- 4 Citric acid
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Correct answer: Acetic acid
Household vinegar is a dilute solution of acetic acid.
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Baking soda is chemically:
- 1 Sodium carbonate
- 2 Sodium hydroxide
- 3 Calcium carbonate
- 4 Sodium bicarbonate
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Correct answer: Sodium bicarbonate
Baking soda is NaHCO₃, sodium hydrogen carbonate.
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Diamond and graphite are both forms of:
- 1 Carbon
- 2 Sulfur
- 3 Phosphorus
- 4 Silicon
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Correct answer: Carbon
They are allotropes of carbon with different structures.
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The pH of a neutral solution at 25 °C is:
- 1 7
- 2 0
- 3 14
- 4 1
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Correct answer: 7
A pH of 7 is neutral, below 7 is acidic and above 7 is basic.
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Rusting of iron needs:
- 1 Nitrogen and water
- 2 Oxygen and water
- 3 Only water
- 4 Only oxygen
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Correct answer: Oxygen and water
Iron rusts when it is in contact with both oxygen and moisture.
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The most abundant gas in the Sun is:
- 1 Oxygen
- 2 Hydrogen
- 3 Carbon
- 4 Helium
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Correct answer: Hydrogen
The Sun is mainly hydrogen, with helium as the second most common.
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The gas used by plants in photosynthesis is:
- 1 Hydrogen
- 2 Carbon dioxide
- 3 Nitrogen
- 4 Oxygen
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Correct answer: Carbon dioxide
Plants take in carbon dioxide and water, and release oxygen.
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Which of the following is a good conductor of electricity?
- 1 Dry wood
- 2 Copper
- 3 Rubber
- 4 Glass
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Correct answer: Copper
Metals such as copper have free electrons, so they conduct well.
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The chemical symbol of gold is:
- 1 Au
- 2 Gd
- 3 Ag
- 4 Go
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The gas used in fire extinguishers is mainly:
- 1 Oxygen
- 2 Nitrogen only
- 3 Carbon dioxide
- 4 Hydrogen
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Correct answer: Carbon dioxide
Carbon dioxide displaces oxygen and cools the fire.
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Water is a compound of:
- 1 Oxygen and carbon
- 2 Hydrogen and nitrogen
- 3 Hydrogen and oxygen
- 4 Hydrogen and carbon
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The hardest natural substance is:
- 1 Graphite
- 2 Diamond
- 3 Steel
- 4 Quartz
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Which gas is released when zinc reacts with dilute sulfuric acid?
- 1 Oxygen
- 2 Hydrogen
- 3 Carbon dioxide
- 4 Chlorine
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The main ingredient of LPG is:
- 1 Methane
- 2 Ethanol
- 3 Acetylene
- 4 Propane and butane
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Correct answer: Propane and butane
Liquefied petroleum gas is mostly propane and butane.
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The ripening of fruits is hastened by the gas:
- 1 Neon
- 2 Ethylene
- 3 Oxygen
- 4 Methane
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Correct answer: Ethylene
Ethylene is a plant hormone that promotes ripening.
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Which metal is liquid at room temperature?
- 1 Lead
- 2 Mercury
- 3 Iron
- 4 Sodium
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The pH of lemon juice is about:
- 1 13
- 2 7
- 3 10
- 4 2
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Soap is made by the reaction of fats with:
- 1 An alkali such as sodium hydroxide
- 2 Salt water only
- 3 Alcohol
- 4 An acid
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Correct answer: An alkali such as sodium hydroxide
This reaction is called saponification.
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The compound used to treat acidity in the stomach is:
- 1 Acetic acid
- 2 Sodium chloride
- 3 Magnesium hydroxide
- 4 Hydrochloric acid
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Correct answer: Magnesium hydroxide
A base such as magnesium hydroxide neutralises excess stomach acid.
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Chlorine is used in water mainly to:
- 1 Add minerals
- 2 Remove salt
- 3 Soften it
- 4 Kill germs