Question

1) what are the characteristics of pure substance ?
2) List two solid non - metals and two gaseous non - metals .​

Answer 1

Answer:

(1)The characteristic of a pure substance is that it only contains atoms of only one kind. It has fixed physical and chemical properties, for example, melting point, boiling point, density, solubility, etc....

(2)solid non metals:--Boron, Carbon

gaseous non metals:--hydrogen, helium

Answer 2

Answer:

Explanation:

1 Pure substances are mostly homogeneous in nature containing only one type of atoms or molecules. These substances mainly have a constant or uniform composition throughout. The substances have fixed boiling and melting points. A pure substance usually participates in a chemical reaction to form predictable products.

2 The Non-metals that are are gases are Hydrogen, Nitrogen and Oxygen. The Non-metals that are are solids are Carbon, Phosphorus, Selenium and Sulfer. The properties of non-metals are not universal or as consistent as the metals.