Last updated on December 9th, 2023 at 09:06 pm
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
