# How many grams of potassium chloride are produced if 25 g of potassium chlorate decompose in the reaction 2KClO_3 -> 2KCl + 3O_2?

Aug 6, 2016

15.2 g of KCl would be produced

#### Explanation:

The general pattern for solving these types of problems is

1. Find "moles" of the known substance
2. Write down the mole ratio using the coefficients from the balanced equation
3. rearrange to solve for the moles "unknown"
4. Convert moles "unknown" to required units (i.e. mass, volume, concentration)

So to solve the problem:

1. Molecular mass of $K C l {O}_{3}$ = 39.10 + 35.45 + 3(16.00)
= 122.55

2. Moles of $K C l {O}_{3}$ = $\frac{25}{122.55}$ = 0.204 mol

3. mol ratio: $m o l K C l / m o l K C l {O}_{3}$ = $\frac{2}{2}$
so
mol of KCl = $\frac{2}{2} \times m o l K C l {O}_{3}$

mol of KCl = $\frac{2}{2} \times 0.204$

mol of KCl = 0.204 mol

4.. molecular mass of KCl = 39.10 + 35.45 = 74.55
mass KCl = $0.204 \times 74.55$ = 15.208 g

Therefore 15.2 g of KCl would be formed.