Physical Change

Q.

What is observed when a solution of potassium iodide is added to a solution of lead nitrate taken in a test tube? What type of reaction is this?

Q.

Give two examples of double displacement reactions with their chemical equations.

Q.

Milk turns sour. is this a chemical or physical change

Q.

The reaction ${\mathrm{Na}}_2{\mathrm{SO}}_4+{\mathrm{BaCl}}_2\to {\mathrm{BaSO}}_4+2\mathrm{NaCl}$ is an example of a/an:

1. Precipitation reaction

2. Double displacement reaction

3. Endothermic reaction

4. All of the above

Q.

Give an example of a reaction in which precipitate is formed.

Q.

Why is the boiling of eggs a chemical change, while the boiling of water is a physical change?

Q.

Give five examples of physical properties.

Q. Burning of paper is a physical change.

1. True
2. False

Q.

What happens in a Chemical reaction?

Q.

List ten changes of occurring around you .classify them into physical and chemical changes .

Q.

Give one example of the double displacement reaction in which

(iv) a white precipitate is formed

Q. Rolling of chapati is an example of physical change and baking of chapati is an example of chemical change.

1. True
2. False

Q. Cutting of wood is which change?

Q.

The boiling of water is a physical change.

1. True
2. False

Q.

Glowing of an electric bulb is a ____ change.

Q. Condensation is a physical change.

1. True
2. False

Q.

Question 8

Paheli’s mother made a concentrated sugar syrup by dissolving sugar in hot water. On cooling, crystals of sugar got separated. This indicates a:
(a) physical change that can be reversed
(b) chemical change that can be reversed
(c) physical change that cannot be reversed
(d) chemical change that cannot be reversed

Q.

Is enthalpy of solution always negative?

Q.

Precipitation reactions produce insoluble salts.

1. True
2. False

Q.

Define dissolving. Is it a physical change?

Q.

Which among the following are physical or chemical changes?

(e) Sublimation of solid ammonium chloride

Q.

Classify the following processes into physical or chemical changes:

(i) The beating of aluminum metal to make aluminum foil.

(ii) Digestion of food.

(iii) Cutting of a log of wood into pieces.

(iv) Burning of crackers.

Q. Differentiate between physical change and chemical change

Q.

Which of the following is not a characteristic of chemical change?

1. It is a permanent change.

2. Exchange of energy take place.

3. No new substance form.

4. The change is irreversible.

Q.

Question 15

Fill in the blanks in the following statements using the words given in the box

(a) Making sugar solution is a …………………. change
(b) A physical change is generally ……………………..
(c) Grinding of wheat grain changes its size. It is a …………….. change.
(d) Iron benches kept in lawns and gardens get ……………… it is a …………….
(e) change because a new ……………… is formed

Q.

Question 19

Give two examples for each of the following cases:
(a) Physical changes which are reversible.
(b) Physical changes which are not reversible.
(c) Chemical changes

Q.

The burning of kerosene in a lantern is a physical or chemical change. Give Reason.

Q.

When ammonium chloride dissolves in water, the temperature of the solution reduces.

1. True
2. False

Q. What is the standard test of carbon dioxide? [2 MARKS]

Q. Is drawing copper into a wire a chemical change or a physical change?