Question

In 0.32 g of methane, the number of moles is:
A. 0.002
B. 0.20
C. 2
D. 0.02

Answer 1

Hint: A mole is the term that is used to denote the quantity of Avogadro number of particles. It is the number of atoms that are$6.022\times {{10}^{23}}$, these numbers make up one mole of any compound. The atomic mass of any substance is equal to these numbers of particles that are considered as 1 mole.
Formula used: Number of moles = $\dfrac{given\,mass}{molar\,mass}$

Complete answer:
A mole is a unit that is used to measure a group of $6.022\times {{10}^{23}}$atoms. 1 mole of any substance is equal to the atomic or molecular mass of that compound that is equal to these numbers of atoms called Avogadro number.
We have been given methane that has chemical formula$C{{H}_{4}}$in the amount 0.32 g, we have to find the number of moles in this amount of methane.
As we know, the molar mass of methane is 16 g/mol this means this amount will have $6.022\times {{10}^{23}}$ atoms that is equal to 1 mole, therefore, the number of moles in 0.32 g of methane will be determined by
Number of moles = $\dfrac{given\,mass}{molar\,mass}$
Number of moles = $\dfrac{0.32\,g}{16\,g/mol}$
Number of moles of methane = 0.02
Hence, the number of moles present in 0.32 gram of methane are 0.02 moles.

So, option D is correct.

Note:
The molar mass of any compound is calculated by adding the atomic mass of the elements present in their respective quantities. Here we have methane that is $C{{H}_{4}}$, which means the molar mass of methane will be mass of [(C) + 4(H)] = [12 + 4] = 16 g/mol. The unit of atomic mass is gram per mole, as this is the mass of$6.022\times {{10}^{23}}$atoms that make up 1 mole.