Ethanol, #CH_3CH_2OH#, has a vapor pressure of 59 mm Hg at 25 °C. What quantity of energy as heat is required to evaporate 125 mL of the alcohol at 25 °C?
The enthalpy of vaporization of the alcohol at 25 °C is 42.32 kJ/mol. The density of the liquid is 0.7849 g/mL.
The enthalpy of vaporization of the alcohol at 25 °C is 42.32 kJ/mol. The density of the liquid is 0.7849 g/mL.
1 Answer
The energy required is 90.1 kJ.
Explanation:
The mass of ethanol is
The moles of ethanol are
The energy required to evaporate a given amount of a liquid is given by the formula
#color(blue)(|bar(ul(color(white)(a/a) q = nΔ_"vap"Hcolor(white)(a/a)|)))" "#
where
In your problem,
∴