Class 7 chemistry physical and chemical change

Tick (✔) The correct choice amongest the following 1. Sublimation of iodine is a : (a) Chemical change (b) Physical change (c) Periodic change (d) Irreversible change 1 Mark(s) 2. When magnesium ribbon is burnt, heat and light are produced. It is an example of : (a) Chemical change (b) Physical and irreversible change (c) Chemical and exothermic change (d) Chemical and endothermic change 1 Mark(s) 3. Powdering of sugar is : (a) Chemical and irreversible change (b) Physical change (c) Reversible change (d) Irreversible change 1 Mark(s) 4. Making ice from water is an example of : (a) Man-made change (b) Chemical change (c) Sublimation (d) Undesirable change 1 Mark(s) 5. Melting of butter is not a : (a) Fast change (b) Desirable change (c) Reversible change (d) Permanent change 1 Mark(s)

Answer

Answers Tick (✔) The correct choice amongest the following 1. (b) Physical change 2. (c) Chemical and exothermic change 3. (b) Physical change 4. (a) Man-made change 5. (d) Permanent change

Write True False for each statement, Rewrite the false statements 1. In an exothermic reaction, heat is given out. 1 Mark(s) 2. In a chemical reaction no new substance is formed. 1 Mark(s) 3. Reaction of zinc pieces with hydrochloric acid is an exothermic reaction. 1 Mark(s) 4. Glowing of an electric bulb is a physical change. 1 Mark(s) 5. Breaking of a glass tumbler is a reversible change. 1 Mark(s) 6. Burning of wood is a chemical change. 1 Mark(s)

Answer

Write True False for each statement, Rewrite the false statements 1. True 2. False (New substance is formed) 3. False (An endothermic reaction) 4. True 5. False (Irreversible change) 6. True

Select the Odd and Out Giving reason 1. Burning of wood, rusting of iron, souring of milk, freezing of water. 1 Mark(s) 2. Freezing of water, magnetising an iron nail, breaking of chalk stick. 1 Mark(s) 3. Rusting, burning, combustion, melting. 1 Mark(s)

Answer

Select the Odd and Out Giving reason 1. freezing of water - others are chemical changes 2. burning of candle - others are physical changes 3. melting - others are chemical changes