# How many grams of K_2CO_3 are needed in order to produce 2.0 mol K_2O?

Jun 2, 2016

$M a s {s}_{\setminus {K}_{2} C {O}_{3}} = 2.8 \times {10}^{2} g$

#### Explanation:

When heated, ${K}_{2} C {O}_{3}$ decomposes according to the following equation:

${K}_{2} C {O}_{3} \to {K}_{2} O + C {O}_{2}$

The molar mass of ${K}_{2} C {O}_{3} = 138.21 \setminus g . m o {l}^{-} 1$

$2.0 \setminus m o l . {K}_{2} O \times \frac{1 \setminus m o l . {K}_{2} C {O}_{3}}{1 \setminus m o l . {K}_{2} O} \times \frac{138.21 \setminus g \setminus {K}_{2} C {O}_{3}}{1 \setminus m o l . {K}_{2} C {O}_{3}}$

$2.0 \setminus \cancel{m o l . {K}_{2} O} \times \frac{1 \setminus \textcolor{red}{\cancel{m o l . {K}_{2} C {O}_{3}}}}{1 \setminus \cancel{m o l . {K}_{2} O}} \times \frac{138.21 \setminus g \setminus {K}_{2} C {O}_{3}}{1 \textcolor{red}{\cancel{\setminus m o l . {K}_{2} C {O}_{3}}}}$

$= 2.8 \times {10}^{2} g$