Question

In the experiment students will create solutions with different ratios of ethanol and water. What is the mole fraction of ethanol when 10.00 mL of pure ethanol is combined with 2.00 mL of water

Answer 1

`x_(et)=0.6068`

Step-by-step explanation:

Hello,

In this case, since the mole fraction of a compound, in this case ethanol, in a binary mixture, in this constituted by both water and ethanol, is mathematically defined as follows:

`x_(et)=(n_(et))/(n_(et)+n_(w))`

Whereas
`n` accounts for the moles in the solution for each species, we must first compute the moles of both ethanol (density: 0.789 g/mL and molar mass: 46.07 g/mol) and water (density: 1g/mL and molar mass: 18.02 g/mol)

`n_(et)=10.00mL\ et*(0.789g\ et)/(mL\ et) *(1mol\ et)/(46.07g\ et)=0.1713mol\ et\\ \\n_w=2.00mL\ w*(1g\ w)/(mL\ w) *(1mol\ w)/(18.02g\ w)=0.1110mol\ w`

Therefore, the mole fraction turns out:

`x_(et)=(0.1713mol)/(0.1713mol+0.1110mol)\\\\x_(et)=0.6068`

Best regards.