Question

convert into moles 12 G of Oxygen gas

Answer 1

Hi !

a)
Given mass = 12 g
Molar mass of oxygen gas ( O₂) = 2 x 16 = 32 g
No: of moles = given mass / molar mass
                      = 12/32 = 0.375 moles
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b) 
Given mass = 20 g
Molar mass of water (H₂O) = 2 x 1 + 16 = 18 g
No: of moles = given mass / molar mass
                     = 20/18 = 1.11 moles

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c) 
Given mass = 22 g
Molar mass of carbon dioxide (CO₂) = 12 + 2 x 16 = 44 g
No: of moles = given mass / molar mass
                     = 22/44 = 0.5 moles
C

Answer 2

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Here we are given the mass of oxygen gas as 12 grams.

Formula of oxygen gas= O2

Molar mass = 2×16 = 32 grams.

We know the formula to calculate the number of moles.

Number of moles = Given mass ÷ Molar mass

= 12 ÷ 32

= 0.375 moles.