Chapter 6


Physical and chemical changes

1) Classify the changes involved in the following processes into physical and chemical changes.

A) Photosynthesis

b) Dissolve sugar in water

c) Combustion of coal

d) Melting of the mind.

(e) Aluminum metal or aluminum sheet manufacturing.

f) Digestion of food

Answer:

a) Chemical change

b) Physical change

c) Chemical change

d) Physical change

e) Physical change

f) Chemical change

2) State the correctness of the following statements. If any sentence is mixed, write the correct sentence for you.

(a) Chemical changes in the wood. (true/false)

Answer: - Misha

b) The process of preparation of soil by soil is physical transformation. (true/false)

Answer:  - Misha

c) The ducts of the registered fat are easily absorbed into the breast. (true/false)

Answer:  - Correct

D) Lo and Mam are different substances. (true/false)

Answer:  - Misha

E) Condensation of water vapor is not a chemical change. (true/false)

Answer: - Correct 

3) Fill in the blanks in the sentences below.

(a) Carbon-dioxide is dissolved in lime-water to prepare _____.

Answer:   Calcium carbonate.

b) Chemical name of baking soda is ______.

Ans:-   Sodium hydrogen carbonate.

c) In the case of Lott, the two methods of resistance are ___ and ____.

Ans:   - Rang, Dastalepan.

D) The change of the body only means the change in the _____ religion.

Answer:   - Physical.

E) Changes in which new substances are produced are called ___ changes.

Answer:   Chemical

4) When the baking soda is mixed with lemon juice, you have created a brownie. What kind of change is this? explain

Ans:-  When the baking powder is mixed with lemon juice, it creates bubbles. This is carbon dioxide. This is a chemical change.

5) When the candle burns, both physical and chemical changes take place. Identify these variables. Let's take an example of how both physical and chemical changes take place.

Ans:-  When the candle burns, two changes take place.

The physical transformation is not easy.

The chemical changes that occur during combustion are the production of carbon dioxide and water.

Let's take a look at it for example -  digestion of food.

This physical change is simply breaking down the diet of Dang.

And the chemical change is H. Chi. Digestion of food by L and enzyme action.

6) You will see that it is a chemical change that is ready.

Ans:  - Be prepared it is a chemical change because dai gakhirlai ghurai nib newari. And the chemical religion of Gakhi and Dai is Beleg Beleg.

7) What are the two Beleg types of transformations of burning wood and cutting wood into pieces? explain

Answer:  Wood undergoes physical changes because of the nature of wood, it undergoes a complete change in shape and size and does not create a new substance.

On the other hand, wood burning is a chemical reaction in which wood is converted to coal and carbon dioxide is released.

8) Describe how copper sulfate crystals are prepared.

Ans:-  Copper sulphate crystals are prepared by crystallization method.

9) If the gate is painted now, it feels like a slow process, read Buzai.

Ans:  - When the materials come in contact with water vapor, water, and oxygen, they get oxidized. If the iron gate is now painted, this color works as a coating or coating on the iron, and water, steam, and water are kept in the Mamre river.

10) In the coastal areas of the desert oceans, what is the golden age? explain

Ans:  - When the materials come in contact with water vapor, water, and oxygen, they get oxidized. From the desert region to the coastal region of the ocean, the humidity increases, which means that the amount of water vapor in the air is higher, so the humidity rises above the soil in summer.

11) The name of the gas used in Pakistan is - Liquefied Petroleum Gas (LPG). Julia is in Chilindarat. After the combustion process, the tetiya e changes (transition-A) and the tetiya e burns (transition-B). The following quotes are given about this change.

Leave the pure sentence

A) Process- A It is a chemical change.

A) Process- B It is a chemical change.

E) Process – Chemical change in both A and B.

(e) This process is also not a chemical change.

Answer:   - a) Process- B It is chemical change.

12) Anaerobic bacteria produce biogas by decomposing animal matter (transformation-A). This biogas fuel is ignited under pressure (version-B). The following quotes are given about this change.

Consider the following sentence:

A) Process- A is only a chemical change.

A) Process- B is only a chemical change.

E) Process – Chemical change in both A and B.

(e) This process is also not a chemical change.

Ans: - e) Process – Chemical change in both A and B.