Question f374d

Apr 3, 2016

$\text{7.7 moles}$

Explanation:

The idea here is that you need to use the molar mass of elemental hydrogen to calculate how many moles you have in that $\text{93-g}$ sample, then use the mole ratio that exists between glucose and hydrogen to find how many moles of glucose would contain that many moles of hydrogen.

So, hydrogen has a molar mass of ${\text{1.00794 g mol}}^{- 1}$, which means that one mole of hydrogen has a mass of $\text{1.00794 g}$. In your case, you will have

93 color(red)(cancel(color(black)("g"))) * "1 mole H"/(1.00794color(red)(cancel(color(black)("g")))) = "92.267 moles H"#

Now, take a look at a molecule of glucose, ${\text{C"_6"H"_color(red)(12)"O}}_{6}$. You can say that one mole of glucose, which is simply a very large collection of molecules of glucose, will contain

• six moles of carbon, $6 \times \text{C}$
• twelve moles of hydrogen, $\textcolor{red}{12} \times \text{H}$
• six moles of oxygen, $6 \times \text{O}$

This means that $92.267$ moles of hydrogen can be used to make

$92.267 \textcolor{red}{\cancel{\textcolor{b l a c k}{{\text{moles H"))) * ("1 mole C"_6"H"_12"O"_6)/(color(red)(12)color(red)(cancel(color(black)("moles H")))) = color(green)(|bar(ul(color(white)(a/a)"7.7 moles C"_6"H"_12"O}}_{6} \textcolor{w h i t e}{\frac{a}{a}} |}}}$

The answer is rounded to two sig figs, the number of sig figs you have for the mass of hydrogen.