Atoms and Molecules

Atoms and Molecules Worksheet-1

1. Hydrogen and oxygen combine in the ratio of 1: 8 by mass to form water. What mass of oxygen will be required to react completely with 4 g of hydrogen?

A. 32 g                B. 16 g                C. 48 g                D. 8 g

2. What is the chemical formula of hydrogen sulphide?

A. H₂S                B. HS                  C. HS₂                D. H₃S

Atoms and Molecules Worksheet-2

11. Calculate the mass of 0.72 gram molecule of carbon dioxide (CO₂)?

A. 33 g                B. 30 g                C. 31.68 g          D. 29 g

12. Calculate the number of moles of iron in a sample containing 10²² atoms of iron.

A. 0.0199 mol                               B. 0.01 mol

C. 1.015 mol                                   D. 0.009 mol

Atoms and Molecules Worksheet-3

21. What is the chemical formula of Sodium oxide and sodium sulphide?

A. NaO and Na₂S                          B. Na₂O and NaS₂

C. NaO₂ and Na₂S                        D. Na₂O and Na₂S

22. The name of the compound represented by chemical formula Al₂(SO₄)₃ is ______.

A. Aluminium sulphate               B. Aluminium sulphite

C. Aluminium sulphide               D. Aluminium thiosulphate