# Question a5115

Mar 22, 2017

Use its molar mass!

#### Explanation:

Let's say that you're dealing with a generic reaction

$\text{A " + " 2B " -> " C}$

Notice that you have a $1 : 1$ mole ratio between $\text{A}$ and $\text{C}$. This tells you that the reaction will consume a number of moles of $\text{A}$ and produce the same number of moles of $\text{C}$.

So, let's say that the reaction consumes $3$ moles of $\text{A}$. The $1 : 1$ mole ratio tells you that it will produce $3$ moles of $\text{C}$.

To convert the number of moles of $\text{C}$ to grams, use its molar mass. Let's say that $\text{C}$ has a molar mass of $x$ ${\text{g mol}}^{- 1}$.

This means that $1$ mole of $\text{C}$ has a mass of $x$ grams. You can thus say that the reaction produced

3 color(red)(cancel(color(black)("moles C"))) * overbrace((x color(white)(.)"g")/(1color(red)(cancel(color(black)("mole C")))))^(color(blue)("the molar mass of C")) = (3x)" g"#

of the product, i.e. $\left(3 x\right)$ $\text{g}$ of $\text{C}$.