9 Is Matter Around Us Pure

Air is regarded as a mixture because:

• Its pressure may very

• Its pressure may very

• Its volume changes under different conditions

• Its composition may vary

Two substances A and B when bought together form a substance C with the evolution of heat. The properties of C are entirely different from those of A and B. the substance C is:

• A compound

• An element

• A mixture

• None of the above

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

• A compound

• A heterogeneous mixture

• An element

• A homogeneous mixture

White gold is used in jewelry and contains two elements, gold and palladium. A jeweler has two different samples that are both identical in appearance and have a uniform composition throughout. What can be said about the samples?

• They are homogeneous mixtures and be classified as metallic alloys.

• The materials are heterogeneous mixtures and can be classified by their components

• The samples have variable compositions and are classified as metallic solutions.

• The samples are heterogeneous mixtures that can be separated using magnetic properties.

In which of the following constituents are present in the ratio?

• Mixture.

• Compound.

• Solution.

• Colloid.

Brass is an example of?

• Homogeneous compound.

• Homogeneous mixture.

• Heterogeneous mixture.

• Heterogeneous compound.

The size of the particle of solute is ............ for colloidal Solution

• <1nm

• >1nm

• Between 1nm and 100nm

• Above 100 nm

Tyndall effect means

• Rays scattered by dust particles

• Rays travelling from one medium to other

• Rays undergoing Refraction

• Rays undergoing totally reflected

Tyndall effect is observed in forests because of

• tress

• high oxygen level

• mist and dust particles in the air

• less sunlight

How would H2O be classified? Check all that apply.

• Atom

• Molecule

• Compound