Question 1

Which of the following is considered matter?

Accepted Answer

Matter is anything that occupies space and has mass. Out of the given options, a chair occupies space and has mass, whereas friendship, smell, and thought are feelings or concepts without physical mass or volume.

Question 2

The SI unit of mass is:

Accepted Answer

The International System of Units (SI) unit for mass is the kilogram (kg). Gram and milligram are smaller units, while litre is a unit of volume.

Question 3

Which state of matter has a fixed volume but no fixed shape?

Accepted Answer

Liquids have a fixed volume because the intermolecular forces keep the particles close together, but they do not have a fixed shape and take the shape of the container because particles can slide over one another.

Question 4

The process of conversion of a solid directly into gas is called:

Accepted Answer

Sublimation is the transition of a substance directly from the solid to the gas state, without passing through the intermediate liquid state (e.g., camphor or dry ice).

Question 5

Boiling point of water on the Kelvin scale is:

Accepted Answer

The boiling point of water in Celsius is 100 °C. To convert Celsius to Kelvin, we add 273.15 (or 273), so 100 + 273 = 373 K.

Matter in Our Surroundings — NCERT Class 9 Science Important Questions & Revision Notes