Last updated on December 9th, 2023 at 09:06 pm
Class 7 Science Physical and Chemical Changes
Test your knowledge of Physical and Chemical Changes in Class 7 Science with our engaging multiple-choice questions (MCQs).
Que: Which of the following is an example of a physical change?
a) Rusting of iron
b) Burning of wood
c) Melting of ice
d) Cooking an egg
Answer: c) Melting of ice
Que: Which of the following is an example of a chemical change?
a) Boiling of water
b) Dissolving sugar in water
c) Freezing of liquid nitrogen
d) Rusting of iron
Answer: d) Rusting of iron
Que: What is rust?
a) A gaseous substance
b) A liquid substance
c) A solid substance
d) A mixture of substances
Answer: c) A solid substance
Que: What causes rusting of iron?
a) Exposure to heat
b) Reaction with oxygen and moisture
c) Contact with acids
d) Mixing with other metals
Answer: b) Reaction with oxygen and moisture
Que: What is the result of rusting on iron objects?
a) Formation of a protective layer
b) Enhancement of durability
c) Prevention of further damage
d) Damage and deterioration over time
Answer: d) Damage and deterioration over time
Que: What is formed when a small piece of magnesium strip burns in a candle flame?
a) Magnesium hydroxide
b) Magnesium oxide
c) Magnesium chloride
d) Magnesium sulfate
Answer: b) Magnesium oxide
Que: How can the chemical change of magnesium burning be represented?
a) Magnesium (Mg) + Oxygen (O2) → Magnesium oxide (MgO)
b) Magnesium (Mg) + Carbon dioxide (CO2) → Magnesium oxide (MgO)
c) Magnesium (Mg) + Hydrogen (H2) → Magnesium oxide (MgO)
d) Magnesium (Mg) + Nitrogen (N2) → Magnesium oxide (MgO)
Answer: a) Magnesium (Mg) + Oxygen (O2) → Magnesium oxide (MgO)
Que: What is the result when the ash (MgO) is mixed with water?
a) Formation of magnesium sulfate
b) Formation of magnesium chloride
c) Formation of magnesium hydroxide
d) Formation of magnesium carbonate
Answer: c) Formation of magnesium hydroxide [Mg(OH)2]
Que: How does the mixture of magnesium oxide and water react with blue and red litmus papers?
a) It turns blue litmus blue
b) It turns blue litmus red
c) It turns red litmus blue
d) It turns red litmus red
Answer: c) It turns red litmus blue
Que: How is the aqueous solution formed by dissolving magnesium oxide in water classified?
a) Acidic
b) Neutral
c) Basic
d) Alkaline
Answer: c) Basic
Que: What substances are formed during the chemical changes involving magnesium?
a) Magnesium chloride and magnesium sulfate
b) Magnesium oxide and magnesium hydroxide
c) Magnesium carbonate and magnesium nitrate
d) Magnesium bromide and magnesium iodide
Answer: b) Magnesium oxide and magnesium hydroxide
Que: What happens when baking soda is added to vinegar?
a) They form a solid precipitate
b) They produce carbon dioxide gas
c) They dissolve completely in water
d) They form a new liquid substance
Answer: b) They produce carbon dioxide gas
Que: What is the result when carbon dioxide gas is passed through lime water?
a) It forms vinegar
b) It forms baking soda
c) It turns lime water milky
d) It changes the color of lime water to blue
Answer: c) It turns lime water milky
Que: Which equation represents the chemical change between carbon dioxide and lime water?
a) Carbon dioxide (CO2) + Lime water [Ca(OH)2] → Calcium carbonate (CaCO3) + Water (H2O)
b) Carbon dioxide (CO2) + Lime water [Ca(OH)2] → Vinegar (CH3COOH) + Water (H2O)
c) Carbon dioxide (CO2) + Lime water [Ca(OH)2] → Sodium chloride (NaCl) + Water (H2O)
d) Carbon dioxide (CO2) + Lime water [Ca(OH)2] → Hydrochloric acid (HCl) + Water (H2O)
Answer: a) Carbon dioxide (CO2) + Lime water [Ca(OH)2] → Calcium carbonate (CaCO3) + Water (H2O)
Que: What is a standard test for carbon dioxide?
a) Turning water into ice
b) Turning lime water milky
c) Changing the color of litmus paper
d) Producing a popping sound
Answer: b) Turning lime water milky
Que: Which of the following is an example of a chemical change?
a) Melting of ice
b) Dissolving salt in water
c) Burning of coal
d) Freezing of liquid nitrogen
Answer: c) Burning of coal
Que: What can chemical changes be accompanied by?
a) Release or absorption of heat
b) Release or absorption of light
c) Release or absorption of radiation
d) All of the above
Answer: d) All of the above
Que: Which of the following is considered a chemical change?
a) Boiling water
b) Ripening of fruits
c) Mixing salt and sugar
d) Melting of chocolate
Answer: b) Ripening of fruits
Que: What is the cause of the browning of apple slices, potatoes, or brinjals?
a) Exposure to sunlight
b) Loss of moisture
c) Chemical change and formation of new substances
d) Microbial growth
Answer: c) Chemical change and formation of new substances
Que: What is the equation that represents the process of rusting?
a) Iron (Fe) + Oxygen (O2) + Water (H2O) → Rust (Iron oxide Fe2O3)
b) Iron (Fe) + Carbon dioxide (CO2) → Rust (Iron oxide Fe2O3)
c) Iron (Fe) + Nitrogen (N2) + Water (H2O) → Rust (Iron oxide Fe2O3)
d) Iron (Fe) + Hydrogen (H2) + Water (H2O) → Rust (Iron oxide Fe2O3)
Answer: a) Iron (Fe) + Oxygen (O2) + Water (H2O) → Rust (Iron oxide Fe2O3)
Que: What are the requirements for rusting to occur?
a) Presence of oxygen only
b) Presence of water or moisture only
c) Presence of oxygen and water or moisture
d) Presence of sunlight and air
Answer: c) Presence of oxygen and water or moisture
Que: How can rusting be prevented on iron articles?
a) Regular application of paint or grease
b) Exposure to sunlight
c) Keeping iron articles dry
d) Use of vinegar or lemon juice
Answer: a) Regular application of paint or grease
Que: What is galvanization?
a) Coating iron with chromium oxide
b) Coating iron with zinc oxide
c) Coating iron with silver
d) Coating iron with gold
Answer: b) Coating iron with zinc oxide
Que: Why are ships made of iron particularly prone to rusting?
a) Due to exposure to sunlight
b) Due to constant contact with air
c) Due to constant exposure to water, especially saltwater
d) Due to lack of proper maintenance
Answer: c) Due to constant exposure to water, especially saltwater
Que: What is crystallization?
a) Formation of gas from a liquid
b) Formation of liquid from a solid
c) Formation of solid crystals from a solution
d) Formation of a solution from a solid
Answer: c) Formation of solid crystals from a solution
Que: Is crystallization considered a physical change or a chemical change?
a) Physical change
b) Chemical change
c) Both physical and chemical change
d) Neither physical nor chemical change
Answer: a) Physical change
Class 7 Science Chapter 4 Heat MCQ
