How many grams are in $2.25$moleof each of the following? ($7.3$)

a.${\mathrm{N}}_2$

b. $\mathrm{NaBr}$

c.${\mathrm{C}}_6{\mathrm{H}}_{14}$

We need to find the mass of given compound i.e. ${\mathrm{N}}_2$

We know that

The molar mass of ${\mathrm{N}}_2$islocalid="1653483910923" $28\mathrm{g}/\mathrm{mole}$

And a mole of the element is equal to molar mass

Therefore,

localid="1653483920741" $$\begin{gathered} 1\mathrm{mole}=28\mathrm{g} \\ 2.25\mathrm{mole}=\frac{28\mathrm{g}\times 2.25\cancel{\mathrm{mol}}}{\cancel{\mathrm{mol}}}=63\mathrm{g} \end{gathered}$$

We need to find the mass of given compound i.e. $\mathrm{NaBr}$

We know that

The molar mass of $\mathrm{NaBr}$islocalid="1653483947784" $103\mathrm{g}/\mathrm{mole}$

And a mole of the element is equal to molar mass

Therefore,

localid="1653483936659" $$\begin{gathered} 1\mathrm{mole}=103\mathrm{g} \\ 2.25\mathrm{mole}=\frac{103\mathrm{g}\times 2.25\cancel{\mathrm{mol}}}{\cancel{\mathrm{mol}}}=231.75\mathrm{g} \end{gathered}$$

We need to find the mass of given compound i.e. ${\mathrm{C}}_6{\mathrm{H}}_{14}$

We know that

The molar mass of ${\mathrm{C}}_6{\mathrm{H}}_{14}$islocalid="1653483966230" $86\mathrm{g}/\mathrm{mole}$

And a mole of the element is equal to molar mass

Therefore,

localid="1653484006578" $$\begin{gathered} 1\mathrm{mole}=86\mathrm{g} \\ 2.25\mathrm{mole}=\frac{86\mathrm{g}\times 2.25\cancel{\mathrm{mol}}}{\cancel{\mathrm{mol}}}=193.5\mathrm{g} \end{gathered}$$