Atoms and Molecules Worksheet-1

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

 

  1. What is the chemical formula of hydrogen sulphide?

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

 

  1. What is the chemical formula of  ammonium sulphate?

A. NH4SO3                                     B. (NH4)2SO3

C. NH4SO4                                     D. (NH4)2SO4

 

  1. What is the chemical formula of  sodium carbonate?

A. Na(CO3)2      B. NaHCO3       C. Na2CO3         D. NaCO3

 

  1. What is the formula of calcium phosphate?

A. CaPO4           B. Ca3(PO4)2     C. Ca2(PO4)3     D. Ca(PO4)2

 

  1. What is the chemical formula of Aluminium hydroxide?

A. AlOH             B. Al(OH)2        C. Al(OH)3        D. Al(OH)4

 

  1. What is the molar mass of water (H2O) ?

A. 10 u                B. 18 u                C. 20 u               D. 16 u

 

  1. What is the molar mass of Sulphur dioxide (SO2)?

A. 32 u                B. 64 u                C. 48 u               D. 28 u

 

  1. What is the molar mass of Ammonium carbonate?

A. 96 u                B. 78 u                C. 90 u               D. 64 u

 

  1. What is the molar mass of sulphuric acid?

A. 90 u               B. 98 u               C. 92 u                D. 82 u

 

Answer:

  1. A

Explanation: The formula of water is H2O

2g of hydrogen combines with 16 g oxygen

4g of hydrogen will combine with

 

  1. A

Explanation:

    

Hydrogen sulphide

            H2S

 

  1. D

Explanation: Ammonium sulphate

         

 

  1. C

Explanation: Sodium carbonate

         

 

  1. B

Explanation: Calcium phosphate           

         

 

  1. C

Explanation: Aluminium hydroxide                                                      

         

 

  1. B

Explanation: Water (H2O)

Molar mass of H2O = (2 × atomic mass of H) + (1 × atomic mass of O) = (2 × 1u) + (1 × 16u) = 18u

 

  1. B

Explanation: Sulphur dioxide (SO2)

Molar mass of SO2 = (1 × atomic mass of S) + (2 × atomic mass of O) = (1 × 32u) + (2 × 16u) = 64u

 

  1. A

Explanation: mmonium carbonate (NH4)2CO3

Molar mass of (NH4)2CO3 = (2 × atomic mass of N) + (2 × (4 × atomic mass of H) + (atomic mass of C) + (3 × atomic mass of O)

Molar mass of (NH4)2CO3 = (2 × 14u) + (2 × (4 × 1u) + (12u) + (3 × 16u) = 96u

 

  1. B

Explanation: Sulphuric acid (H2SO4)

Molar mass of (H2SO4) = (2 × atomic mass of H) + (1 × atomic mass of S) + (4 × atomic mass of O) + (2 × 1u) + (4 × 16u) = 98u