Question

Calculate the number of moles for the 52 g of He (finding mole from mass).

NCERT Class IX
Sciences - Main Course Book

Chapter 3. Atoms and Molecules

Answer 1

52 grams of He have 13 moles.

Given: 52 g of He.

To find: The number of moles.

Solution:

He is an inert gas residing at period one of the periodic table.

It has a molar mass of 4 grams.

One mole of He has a molar mass of 4 grams.

Thus we can say, 4 grams of He has one mole.

Thus 52 grams of will have-

$\frac{52}{4} = 13$

52 grams of He have 13 moles.

Answer 2

Given: 52 g Helium

To find: Number of moles in 52 g Helium

Number of moles = Given mass of element divided by molar mass of the given element.

Molar mass of Helium = 4 g/mol

Substituting the values in the formula we get,

Number of moles of Helium= 52 /4 = 13

Hence, the number of moles is 13 mol.