Question

3. Substance A does not have fixed melting and boiling points. Substance B has fixed melting
and boiling points and cannot be broken down by chemical reactions. Substance Chas fixed
melting and boiling points and breaks down into simpler substances when heated. Identify
which substance is:
a. an element,
b. a compound;
a mixture.​

Answer 1

Answer:

The boiling point of a substance is where the liquid phase changes into gas phase. The melting point of a substance is where the solid phase changes into the liquid phase. Since air is a mixture of gases, so, all the different gases have different melting and boiling points. So, air has no boiling point and it also has no melting point. Gold is a metal, ethanol is a type of alcohol and oxygen is type of gas which have only atoms of oxygen. Hence, remaining all three have fixed substances and therefore have fixed melting/ boiling point. But air does not.

How satisfied are you with the answer?

Answer 2

Answer:

a. an element – Gold

b. a compound – Ethanol

c. a mixture – oxygen