Question

Water is a pure substance. Which of the following is true about water?

a
A chemical change is required to separate the elements present in it.

b
A physical change is required to separate the elements present in it.

c
It is made up of two compounds, each with a different set of atoms.

d
It is made up of an element and a compound.

Answer 1

A chemical change is required to separate the elements present in it.

Step-by-step explanation:

The only true statement from the choices given is that water as a pure substance requires a chemical change to separate the elements present in it.

Water is a molecule consist of two atoms of hydrogen and one atom of oxygen.

• The atoms are covalently bonded together.
• A chemical process, the electrolysis of water is often used to separate the atoms of a water.
• Physical changes cannot be used to separate the atoms of water.
• Water is a compound which consists of two elements.

Therefore, we see that only the first choice satisfies this problem.