Question

*89. a flask that can hold 158 g of water at 4°c can hold only 127 g of ethanol at the same temperature. what is the density of ethanol?

Explanation:

Step1: Find volume of the flask

The density of water at $4^{\circ}C$ is $
ho_{water}= 1\ g/cm^{3}$. Using the density formula $
ho=\frac{m}{V}$, we can find the volume of the flask. Since $V = \frac{m}{
ho}$, for water $m_{water}=158\ g$ and $
ho_{water}=1\ g/cm^{3}$, so $V=\frac{m_{water}}{
ho_{water}}=\frac{158\ g}{1\ g/cm^{3}} = 158\ cm^{3}$.

Step2: Calculate density of ethanol

The mass of ethanol $m_{ethanol}=127\ g$ and the volume of the flask (which is the volume of ethanol) $V = 158\ cm^{3}$. Using the density formula $
ho=\frac{m}{V}$, for ethanol $
ho_{ethanol}=\frac{m_{ethanol}}{V}=\frac{127\ g}{158\ cm^{3}}\approx0.804\ g/cm^{3}$.

Answer:

$0.804\ g/cm^{3}$