What is the numerical setup for calculating the number of moles of $CO_2$ present in 11 grams of $CO_2$ ?

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Answer 1 · 2017-01-01T01:37:20

Here's how to get the numerical setup.

You must use the molar mass of $"CO"_2$ as a conversion factor to convert grams of $"CO"_2$ to moles of $"CO"_2$ .

The molar mass of $"CO"_2$ is 44.01 g/mol.

Thus, the conversion is either (a) $("44.01 g CO"_2)/("1 mol CO"_2)$ or (b) $("1 mol CO"_2)/("44.01 g CO"_2)$ .

You want an equation like

$"11 g CO"_2 × "conversion factor" = "? mol CO"_2$

The conversion factor must have the desired units of your answer ( $"mol CO"_2$ ) on top, so you choose option (b).

The numerical setup is

$11 color(red)(cancel(color(black)("g CO"_2))) × ("1 mol CO"_2)/(44.01 color(red)(cancel(color(black)("g CO"_2))))= "0.25 mol CO"_2$

Note that the units of " $"g CO"_2$ " cancel and give you the correct units for the answer.

What is the numerical setup for calculating the number of moles of CO_2CO_2 present in 11 grams of CO_2CO_2?