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Physical and chemical changes

The gas we use in the kitchen is called liquified petroleum gas (LPG). In
the cylinder it exist as a liquid. When it comes out from the cylinder it
becomes a gas (Change – A) then it burns (Change – B). The following
statements pertain to these changes. Choose the correct one.
(i) Process – A is a chemical change.
(ii) Process – B is a chemical change.
(iii) Both processes A and B are chemical changes.
(iv) None of these processes is a chemical change.

Mensuration

In question, state whether the statement are true (T) or false (F).

Two cuboids with equal volumes will always have equal surface areas.

Mensuration

In question, state whether the statement are true (T) or false (F).

The surface area of a cuboid formed by joining face to face 3 cubes of
side x is 3 times the surface area of a cube of side x.

Physical and chemical changes

Explain why rusting of iron objects is faster in coastal areas than in
deserts.

Mensuration

In question, state whether the statement are true (T) or false (F).

The areas of any two faces of a cuboid are equal

Physical and chemical changes

Explain how painting of an iron gate prevents it from rusting.

Physical and chemical changes

Describe how crystals of copper sulphate are prepared.

Mensuration

In question, state whether the statement are true (T) or false (F).

The areas of any two faces of a cube are equal.

Physical and chemical changes

Explain why burning of wood and cutting it into small pieces are
considered as two different types of changes.

Mensuration

Two cylinders of same volume have their radii in the ratio 1:6, then
ratio of their heights is __________.