Question

Calculate the molar mass of the following.
a) Potassium dichromate (K2Cr2O7)
b) Water(H2O)
c) Ethanol(C2H5OH)

Answer 1

Answer:

a) 294.185 g/mol

b) 18.01528 g/mol

c) 46.07 g/mol

Answer 2

Answer:-

(a) 294 g/mol

(b) 18 g/mol

(c) 46 g/mol

Explanation:-

Firstly, let's see the molar masses of some elements which will be required.

• Molar mass of Potassium (K) = 39g/mol

• Molar mass of Chromium (Cr) = 52g/mol

• Molar mass of Oxygen (O) = 16g/mol

• Molar mass of Carbon (C) = 12g/mol

• Molar mass of Hydrogen (H) = 1g/mol

So now, let's calculate the molar masses of the given compounds.

Potassium dichromate :-

Chemical formula - K₂Cr₂O₇

Molar mass :-

= 39×2 + 52×2 + 16×7

= 78 + 104 + 112

= 294g/mol

Water :-

Chemical formula - H₂O

Molar mass :-

= 1×2 + 16

= 2 + 16

= 18g/mol

Ethanol :-

Chemical formula - C₂H₅OH

Molar mass :-

= 12×2 + 1×5 + 16 + 1

= 24 + 5 + 17

= 46g/mol