Question

Ethanol (density = 0.789 g/ml) combusts and produces 34.8 g h2o. what was the original volume of the ethanol?

Answer 1

I'm not completely sure but I think it is 27.4572. Hope I helped a little.

Answer 2

Answer : The original volume of the ethanol is 37.5 mL

Explanation :

The balance chemical reaction will be,

$C2H_5OH+3O_2\rightarrow 2CO_2+3H_2O$

First we have to calculate the moles of $H_2O$.

$\text{ Moles of }H_2O=\frac{\text{ Mass of }H_2O}{\text{ Molar mass of }H_2O}=\frac{34.8}{18g/mole}=1.93moles$

Now we have to calculate the moles of ethanol.

From the balanced reaction we conclude that,

As, 3 moles of $H_2O$ produce from 1 mole of ethanol

So, 1.93 moles of $H_2O$ produce from $\frac{1.93}{3}=0.643$ mole of ethanol

Now we have to calculate the mass of ethanol.

$\text{ Mass of ethanol}=\text{ Moles of ethanol}\times \text{ Molar mass of ethanol}$

$\text{ Mass of ethanol}=(0.643moles)\times (46g/mole)=29.6g$

Now we have to calculate the volume of ethanol.

$Density=\frac{Mass}{Volume}$

$0.789g/mL=\frac{29.6g}{Volume}$

$Volume=\frac{29.6g}{0.789g/mL}=37.5mL$

Therefore, the original volume of the ethanol is 37.5 mL