Question

How many molecules of ethane gas, C2H6 are in 15 grams of the compound?

Answer 1

3.01×10²³molecules.

Explanations:

The formula for the number of molecules of a compound given the number of moles is expressed as:

`nu\text{mber of molecules=moles}*6.02*10^(23)`

Get the moles of ethane gas using the formula:

`\begin{gathered} \text{moles of ethane=}\frac{Mass\text{ of ethane}}{Molar\text{ mass of ethane}} \\ \text{Moles of ethane=}(15)/(2(12)+1(6)) \\ \text{Moles of ethane}=(15)/(30)\text{moles} \\ \text{Moles of ethane}=0.5\text{moles} \end{gathered}`

Determine the required number of molecules of ethane

`\begin{gathered} nu\text{mber of mol}ecules=0.5*6.02*10^(23) \\ nu\text{mber of mol}ecules=3.01*10^(23) \end{gathered}`

Hence the molecule of ethane gas that is in 15 grams of the compound is 3.01×10²³molecules.