How many moles of molecules are in 35 g of octane, $C_8H_18$ ?

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Answer 1 · 2017-04-11T15:54:46

There are 0.307 moles of molecules in 35 g of octane.

You start by finding the molar mass of octane, $C_8H_18$

This is 114 grams, because there are eight moles of carbon atoms and eighteen moles of hydrogen atoms in each mole of octane molecules.

So, we total up 8 x 12 (for the carbon) and 18 x 1 (for the hydrogen).

Next, take the given mass, and divide by this molar mass:

$35 g -: 114 g/"mol" = 0.307 "mol"$

That's it! This answer is the number of moles of octane molecules contained in the 35 grams of the compound.

How many moles of molecules are in 35 g of octane, C_8H_18C_8H_18?