Practice

Changes Around Us: Physical and Chemical — Practice

15 questions 15 min Recall + understand

Q1. A change in which only physical properties like shape, size or state alter and no new substance is formed is called
- A. A chemical change
- B. A physical change
- C. A combustion reaction
- D. Weathering
Q2. Which of the following is the most important identifying feature of a physical change?
- A. A new substance is formed
- B. Heat is always released
- C. No new substance is formed
- D. A chemical equation can be written
Q3. A change in which one or more new substances are formed is called
- A. A physical change
- B. A chemical change
- C. Erosion
- D. Reversible change
Q4. The process through which new substances are formed in a chemical change is called
- A. Chemical reaction
- B. Physical change
- C. Condensation
- D. Erosion
Q5. When a student blows air through a straw into lime water, the lime water
- A. Stays unchanged
- B. Turns milky (cloudy)
- C. Turns deep red
- D. Catches fire
Q6. The white insoluble substance formed when carbon dioxide reacts with lime water is
- A. Calcium hydroxide
- B. Calcium carbonate
- C. Sodium chloride
- D. Magnesium oxide
Q7. When a pinch of baking soda is added to vinegar, the gas evolved is
- A. Oxygen
- B. Nitrogen
- C. Carbon dioxide
- D. Hydrogen
Q8. Baking soda mentioned in Activity 5.4 is chemically known as
- A. Sodium chloride
- B. Sodium hydrogen carbonate
- C. Calcium carbonate
- D. Magnesium oxide
Q9. The new brown-coloured substance formed when iron rusts is
- A. Magnesium oxide
- B. Calcium carbonate
- C. Iron oxide
- D. Sodium chloride
Q10. A chemical reaction in which a substance reacts with oxygen and produces heat and/or light is called
- A. Rusting
- B. Combustion
- C. Condensation
- D. Weathering
Q11. When a magnesium ribbon is burnt in air, the white powder formed is
- A. Magnesium oxide
- B. Calcium carbonate
- C. Iron oxide
- D. Sodium hydrogen carbonate
Q12. The minimum temperature at which a substance catches fire is called its
- A. Boiling point
- B. Melting point
- C. Ignition temperature
- D. Solidification point
Q13. The three components of the fire triangle required for combustion are
- A. Fuel, water, oxygen
- B. Fuel, oxygen, heat
- C. Heat, light, oxygen
- D. Fuel, nitrogen, heat
Q14. The process in which rock pebbles, soil and sediments are broken down and moved from one location to another by wind and flowing water is called
- A. Weathering
- B. Erosion
- C. Combustion
- D. Rusting
Q15. The physical and chemical changes in rocks that eventually lead to the formation of soil are collectively called
- A. Erosion
- B. Weathering
- C. Condensation
- D. Combustion

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