Question

10) State difference between physical and chemical change.

11) Hydrogen being highly inflammable gas and oxygen being supporter of combustion, yet water which is compound of hydrogen and oxygen is used to extinguish fire. Why?

12) 15 ml of water and 10 ml of sulphuric acid are to be mixed in a beaker.
a. State the method that should be followed.
b. What is this process called?

13) A white colored powder is used by doctors for supporting fractured bones.
a. Write chemical name and formula of powder
b. When this white powder is mixed with water a hard solid mass is obtained. Write th
chemical equation for the change.

14) Explain the action of dil. HCl on the following with chemical equation:
a. Magnesium ribbon
b. Sodium hydroxide
c. Crushed egg shells​

Answer 1

Answer:

A change in which the molecules are rearranged, but their internal composition remains same is called physical change.

The change in which the substance transform into a new substance, having a different chemical composition is known as chemical change.

Hope that this helps you

Answer 2

Answer:

PHYSICAL CHANGES

- The chemical composition of a substance does not change.

- Change is only in the state of matter and not in the chemical identity.

-Examples include- Vaporising of water and dissolution of sugar in water.

- Most changes are reversible.

- No new substances are formed. For example,

Ice → Water → Steam

 CHEMICAL CHANGES

- The chemical composition of a substance changes.

- Change is in chemical identity, but may or may not be in the state of matter.

- Examples include- Rusting of Iron, cooking of food etc.

- Most changes are irreversible.

- New substances are formed.For example,

methane → carbon dioxide and water