# 12.00 moles of NaClO3 will produce how many grams of O2? 2 NaClO3 ---> 2 NaCl + 3 O2

May 14, 2014

How many grams of ${O}_{2}$ are produced if 12.00 moles of $N a C l {O}_{3}$?

We begin with a balanced chemical equation that is provided in the question.

$2 N a C l {O}_{3} \to 2 N a C l + 3 {O}_{2}$

Next we determine what we have and what we want.
We have 12.00 moles of $N a C l {O}_{3}$ and we want grams of ${O}_{2}$.

We set up a roadmap to solve the problem

$m o l N a C l {O}_{3} \to m o l {O}_{2} \to g r a m s {O}_{2}$

We need the molar mass ($g f m$) of ${O}_{2}$.
${O}_{2}$ = 32.0 g/mol

We need the mole ratio between $N a C l {O}_{3}$:${O}_{2}$ 2:3. This comes from the coefficients of the balanced chemical equation.

Now we set up conversion factors following the roadmap from above.
Unit we want in the numerator, unit to cancel in the denominator.

$12.00 m o l N a C l {O}_{3} x \frac{3 m o l {O}_{2}}{2 m o l N a C l {O}_{3}} x \frac{32.0 . g {O}_{2}}{1 m o l {O}_{2}} =$

Multiply the numerators, and divide the denominators.

The outcome is
$576.0 g {O}_{2}$
will be produced from 12.00 moles $N a C l {O}_{3}$

SMARTER TEACHER

The number of moles for NaClO3 = 12 moles
The number of moles for O2 = 18 moles
Molar mass of O2 = 32 g/mol

#### Explanation:

If 2 moles of NaClO3 gives you 3 moles of O2,
it's because the mole ratio between NaClO3 : O2 is 2 : 3.
Then 12 moles of NaClO3 must give you [12 ÷ 2 then$\times$3] = 18 moles of O2.
You have found the number of moles (n) for O2.

Note that number of moles (n) = mass of substance (m)$\div$molar mass (M).
$n = m \div M$

The next step is to find out what is the molar mass (M) of O2.
If you look into your periodic table, the atomic weight is equivalent to the molar mass.
The molar mass of one O is = 16 g/mol.
Since there are two O present in the reaction (refer to equation), the molar mass of O2 is [16 g/mol$\times$2] = 32 g/mol
You've now found the molar mass (M).

The final step is to find out the mass (m) of O2. Since you found the number of moles (n) and molar mass (M), you can now find out the mass of substance.
Looking back at the formula $n = m \div M$, to find m, we need to make the formula look: m = n$\times$M.
The mass of O2 is [18 moles $\times$32 g/mol] = 576 grams.

Overall, 12 moles of NaClO3 will produce 576 grams of O2.