Question

Calculate the Molecular or Formula massof each of the following:

Answer 1

Explanation:

Molar mass  

The mass present in one mole of a specific species .

The molar mass of a compound , can easily be calculated as the sum of the all the individual atom multiplied by the number of total atoms .

(a) P₄

Molar mass of of the atoms are -

Phosphorous , P = 31 g/mol

Molecular mass of  P₄ = ( 4 * 31 ) = 124 g/mol .

(b) H₂O

Molar mass of of the atoms are -

Hydrogen , H = 1 g/mol

oxygen , O = 16 g/mol.

Molecular mass of H₂O = ( 2 * 1 ) + ( 1 * 16 ) = 18 g/mol

(c) Ca(NO₃)₂

Molar mass of of the atoms are -

calcium , Ca = 40 g/mol

nitrogen, N = 14 g/mol

oxygen , O = 16 g/mol.

Molecular mass of  Ca(NO₃)₂ = ( 1 * 40 ) + ( 2 * 14 ) + ( 6 * 16 ) = 164 g/mol.

(d)CH₃CO₂H (acetic acid)

Molar mass of of the atoms are -

Carbon , C = 12 g/mol.

oxygen , O = 16 g/mol.  

Hydrogen , H = 1 g/mol

Molecular mass of CH₃CO₂H =( 2 * 12 ) + (2 * 16 ) + (4 * 1 ) = 60 g/mol.

(e) C₁₂H₂₂O₁₁ (sucrose, cane sugar).

Molar mass of of the atoms are -

Carbon , C = 12 g/mol.

oxygen , O = 16 g/mol.  

Hydrogen , H = 1 g/mol

Molecular mass of C₁₂H₂₂O₁₁ = (12 * 12 ) + ( 22 * 1 ) + ( 11 * 16 ) = 342 g/mol.