SAT II Chemistry : Molar Mass

Study concepts, example questions & explanations for SAT II Chemistry

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Example Questions

Example Question #2 : Stoichiometry

What is the approximate percentage of carbon by mass in heptane, which has the molecular formula ?

Possible Answers:

Correct answer:


First, calculate the molar mass of heptane, which is

We can calculate the percentage of carbon by mass in heptane by creating a fraction of the mass of carbon over the mass of the entire molecule and converting it into a percentage:

For every 100 g of heptane, 84 g must come from carbon. This means that the percentage of carbon by mass is 

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