is matter around us pure

A sample contains two substances and has uniform properties. The sample is ________?

• A compound.

• A heterogeneous mixture.

• An element.

• A homogeneous mixture.

Rusting of an article made up of iron is called

• (a) corrosion and it is a physical as well as chemical change

• (b) dissolution and it is a physical change

• (c) corrosion and it is a chemical change

• (d) dissolution and it is a chemical change

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

• (a) Centrifugation

• (b) Fractional distillation

• (c) Evaporation

• (d) Tunneling

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

• (a) Dispersion

• (b) Tyndall effect

• (c) Brownian movement

• (d) Oscillation

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

• (a) a compound

• (b) an element

• (c) a molecule

• (d) a mixture

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

• (a) Miscible liquids

• (b) Immiscible liquids

• (c) Saturated liquids

• (d) Super saturated liquids

How one can separate ammonium chloride from a mixture containing ammonium chloride and sodium chloride?

• (a) Precipitation

• (b) Sublimation

• (c) Chromatography

• (d) Cetrifugation

The amount of solute present per unit volume or per unit mass of the solution/solvent is known as

• (a) Composition of solute

• (b) Concentration of a solvent

• (c) Concentration of a solute

• (d) Concentration of a solution

Tyndall effect is observed in forests because of

• tress

• high oxygen level

• mist and dust particles in the air

• less sunlight

concentration of 36g of NaCl in 100 g of water is

• 23%

• 26.47%

• 29.32%

• 21.11%