Question

How many grams are in $0.150$moleof each of the following? ($7.3$)

a.$\mathrm{K}$

b. ${\mathrm{Cl}}_2$

c.$N{a}_{2}C{O}_3$

Short answer

(a) The mass of $K$in localid="1653465720314" $0.150$moleis localid="1653465731820" $5.87$g

(b) The mass of $C{l}_2$in localid="1653465747900">0.150moleis localid="1653465893353" role="math" $10.6$g

(c) The mass of ${\mathrm{Na}}_2{\mathrm{CO}}_3$in localid="1653465933393" $0.150$moleis localid="1653465947867" $15.9$g

Step-by-step solution

Part (a) Step 1: Given information

We need to find the mass of given element i.e. $K$

Part (a) Step 2: Explanation

We know that

Molar mass of $\mathrm{K}$is localid="1653483743125" $39\mathrm{g}/\mathrm{mole}$

And a mole of the element is equal to molar mass

Therefore,

localid="1653483757545" $$\begin{gathered} 1\mathrm{mole}=39\mathrm{g} \\ 0.15\mathrm{mole}=\frac{39\mathrm{g}\times 0.150\cancel{\mathrm{mole}}}{\cancel{\mathrm{mole}}}=5.87\mathrm{g} \end{gathered}$$

Part (b) Step 1: Given information 

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

Part (b) Step 2: Explanation 

We know that

Molar mass of ${\mathrm{Cl}}_2$islocalid="1653483785033" $71\mathrm{g}/\mathrm{mole}$

And a mole of the element is equal to molar mass

Therefore,

localid="1653483798412" $$\begin{gathered} 1\mathrm{mole}=71\mathrm{g} \\ 0.150\mathrm{mole}=\frac{71\mathrm{g}\times 0.150\cancel{\mathrm{mol}}}{\cancel{\mathrm{mol}}}=10.6\mathrm{g} \end{gathered}$$

Part (c) Step 1: Given information 

We need to find the mass of given compound i.e. ${\mathrm{Na}}_2{\mathrm{CO}}_3$

Part (c) Step 2: Explanation 

We know that

Molar mass of ${\mathrm{Na}}_2{\mathrm{CO}}_3$islocalid="1653483821807" $106\mathrm{g}/\mathrm{mole}$

And a mole of the element is equal to molar mass

Therefore,

localid="1653483833462" $$\begin{gathered} 1\mathrm{mole}=106\mathrm{g} \\ 0.150\mathrm{mole}=\frac{106\mathrm{g}\times 0.150\cancel{\mathrm{mol}}}{\cancel{\mathrm{mol}}}=15.9\mathrm{g} \end{gathered}$$