Unit - 1.1 Matter and its Composition — CHEMISTRY STD 7 — Question

Is the process of digestion a physical change?

A natural change can also be a desirable change.

Litmus is a natural indicator obtained from a plant.

Magnesium is used in making light weight alloys of aluminum.

Sand is an oxide of silicon.

Ice at 0°C has a lower density than water at 4°C and hence it floats on water.

A pure substance is composed of the same kind of particle throughout.

The smallest unit of a pure substance which always exists independently and can retain all the physical and chemical properties of that substance is called a molecule.

In a skeletal equation, the mass of the reactants is equal to the mass of the products.

The pure water can be obtained from seawater by the process of filtration.