Question

A molecule of pentane is made of 5 carbon atoms and 12 hydrogen atoms. A collection of pentane molecules has 3.01 x 10^24 carbon atoms. How many hydrogen atoms are in the collection?

Answer 1

$\frac{5}{12} = \frac{x}{3.01 \times {10}^{24} } \\ \frac{5(3.01 \times {10}^{24} )}{12} = x \\ x = 1.25 \times {10}^{24} atoms$