Chapter 12, Problem 1CQ

Which has more mass, a mole of Ne gas or a mole of N₂ gas?

To determine

To find: Which has more mass, a mole of Ne or ${\text{N}}_2$ gas.

Answer to Problem 1CQ

A mole of $\underset{\_}{{\text{N}}_2}$ has more mass than mass of a mole of Ne gas.

Explanation of Solution

Formula used:

Write the expression to find molecular mass.

$\text{Molecular}\text{mass}=\text{Number}\text{of}\text{atoms}\times \text{Atomic}\text{mass}$ (1)

Explanation:

A molecular mass of a substance is the mass in grams of 1 mole of substance.

Atomic mass of ${\text{N}}_2$ gas is 14 amu. So, a mole of ${\text{N}}_2$ gas has weight of 14 g. Similarly, atomic mass of Ne gas is 20 amu. So, a mole of Ne gas has weight of 20 g.

The number of atoms present in ${\text{N}}_2$ is 2 and number of atom present in Ne gas is 1.

Substitute 2 for Number of atoms and 14 g for Atomic mass in equation (1),

$\begin{array}{c}\text{Molecular}\text{mass}=\text{2}\times \text{14}\text{g}\\ =\text{28}\text{g}\end{array}$

So, the molecular mass of ${\text{N}}_2$ gas is 28 g.

Substitute 1 for Number of atoms and 20 for Atomic mass in equation (1),

$\begin{array}{c}\text{Molecular}\text{mass}=\text{1}\times \text{20}\text{g}\\ =\text{20}\text{g}\end{array}$

So, the molecular mass of Ne gas is 20 g.

By comparing the computed values, ${\text{N}}_2$ gas having more molecular weight than the Ne gas.

Therefore, A mole of $\underset{\_}{{\text{N}}_2}$ has more mass than mass of a mole of Ne gas.