Question

How many grams of CO2 are used when 7.0 g of O2 are produced?

Answer 1

7.0 g O2 X (1 mol O2 / 32 g O2) X (4 mol KO2 / 3 mol O2) X (71.1 g/mol) = 21 g KO2

Answer 2

Answer : The mass of $CO_2$ used are 9.68 grams.

Explanation : Given,

Mass of $O_2$ = 7.0 g

Molar mass of $O_2$ = 32 g/mole

Molar mass of $CO_2$ = 44 g/mole

The balanced chemical reaction will be,

$CO_2\rightarrow C+O_2$

First we have to calculate the moles of $O_2$.

$\text{ Moles of }O_2=\frac{\text{ Mass of }O_2}{\text{ Molar mass of }O_2}=\frac{7.0g}{32g/mole}=0.22moles$

Now we have to calculate the moles of $CO_2$.

From the balanced chemical reaction we conclude that,

As, 1 mole of $O_2$ produced form 1 mole of $CO_2$

So, 0.22 mole of $O_2$ produced form 0.22 mole of $CO_2$

Now we have to calculate the mass of $CO_2$.

$\text{ Mass of }CO_2=\text{ Moles of }CO_2\times \text{ Molar mass of }CO_2$

$\text{ Mass of }CO_2=(0.22moles)\times (44g/mole)=9.68g$

Therefore, the mass of $CO_2$ used are 9.68 grams.