Physical and Chemical Changes

Q. When calcium carbonate is heated, it gives calcium oxide and carbon dioxide. Is this reaction reversible or irreversible ?

Q.

Differentiate between periodic and non-periodic changes.

Q.

Formation of curd from milk is a physical change.

1. True

2. False

Q. Bursting of a balloon and burning of fuel are _______ and _______ changes respectively.

1. chemical and periodic
2. physical and chemical
3. chemical and physical
4. physical and periodic

Q.

Which of the following is a chemical change?

1. Cooking of vegetables
2. Cutting of fruits
3. Boiling of water
4. Melting of solids

Q.

Dew formation is a chemical change

1. True
2. False

Q.

Explain with an experiment that the melting of wax is a physical change.Observe the changes around you and make a list of these changes and categories them into physical and chemical change.(At least 10 for each)

Q.

Conversion of frost to water vapour is an example of

1. photochemical reaction

2. none of the above

3. endothermic reaction

4. exothermic reaction

Q.

What are the advantages of the classification of elements?

Q.

Which species has the highest water content:

1. Adult human being

2. Human babies

3. Sea horse

4. Jellyfish

Q.

Give two examples of periodic changes.

Q.

Differentiate between a periodic and non-periodic change

Q.

A lot of heat energy is usually absorbed or given out during a physical change

1. True
2. False

Q. Which of the following is/are chemical change(s)?

1. Dissolving of an iron nail in acid
2. Breaking of ice
3. Charring of sugar
4. Dissolving alcohol in water

Q. Which of the following is not a chemical change?

1. Burning coal
2. Respiration
3. Cooking egg
4. Cutting wood

Q. how does a candle burn? write the steps of changes involved

Q.

The formation of day and night is a periodic change.

1. True
2. False

Q.

What physical observation can confirm that iron has rusted?

Q. Which of the following are true about heating water?

1. It is an irreversible change.
2. New substance(s) is/are formed after water is heated.
3. Change in state.
4. It is a physical change.

Q.

6. An object expands on heating. Write one use of it.

Q.

Rusting of iron is an example of chemical change.

1. True
2. False

Q.

Which of the following are examples of a chemical reaction?

1. Conversion of steam to water
2. Rusting of iron
3. Cutting of wood
4. All of the above

Q.

(Iodine/Ammonia) ___________ is a sublimable substance.

Q.

Assertion:- The products formed in a chemical reaction has entirely different properties to that of reactants.

Reason:- Bonds between the atoms of reactants break and form new bonds to make products.

1. Assertion:- True

   Reason:- True

   Reason is not the correct explanation of assertion

2. Assertion:- True

   Reason:- True

   Reason is the correct explanation of assertion

3. Assertion:- True

   Reason:- False

4. Assertion:- False

   Reason:- False

Q.

Define curdling.

Q.

Camphor melts on heating.

1. True

2. False

Q.

Explain by giving example that change involves energy.

Q.

Why does a glass tumbler crack when very hot milk is poured into it?

Q. Which of the following is/are undesirable changes?

1. Rusting
2. Ripening of fruit
3. Deforestation
4. Cooking of food

Q. Which of the following processes does not involve the absorption or evolution of heat?

1. Rolling of dough
2. Combustion of fuel
3. Respiration
4. Lighting a candle