Class 9 Ch 2 Science

Which of the following is an element?

• NaCl

• HI

• HF

• He

The only liquid non-metal is ____________.

By which method we can separate the mixture of NH4Cl and NaCl?

• Sublimation

• Condensation

• Centrifugation

• None

When the liquid is spun rapidly, the denser particle are forced to set at the bottom and the lighter particles started coming at the top. This principle is used in:

• Centrifugation

• Fractional Distillation

• Evaporation

• Tunneling

The continous zig-zag movement of colloidal particles in a dispersion medium is called

• Dispersion

• Tyndall effect

• Brownian movement

• None

A pure substance which is made up of only one kind of atom and cannot be broken into two or more simpler substances by physical or chemical means is referred to as:

• Compound

• Element

• Molecule

• Mixture

Name the non metal which is good conductor of electricity.

When two liquids do not mix, they form two separate layers are known as miscible liquids.

• True

• False

According to the definition of pure substance, which of the following is a pure substance?

• Ice

• Mercury

• Iron

• All of these

Which of the following property does not describe a compound?

• It is composed of two or more elements

• It is a pure substance

• It cannot be separated into constituents by physical means

• It is mixed in any proportion by mass.