Question

Enter your answer in the provided box. From the data below, calculate the total heat (in J) needed to convert 0.602 mol of gaseous ethanol at 300.0°C and 1 atm to liquid ethanol at 25.0°C and 1 atm: b.p. at 1 atm: 78.5°C ΔH o vap : 40.5 kJ/mol cgas: 1.43 J/g·°C cliquid: 2.45 J/g·°C

Answer 1

Q = mc∆T

Q = heat energy (Joules, J), m = mass of a substance (kg)

c = specific heat (units J/kg∙K), ∆ is a symbol meaning "the change in"

∆T = change in temperature (Kelvins, K)

gaseous ethanol going to get following 3 changes

1) As a gas the temperature reduces from  300.0°C to 78.5°C

2) Gas is converted to liquid

3) As a liquid the temperature redcues to 78.5°C to  25.0°C

Amount of heat needed

Q = 0.602 x 1.43 x (300-78.5) + 0.602 x 40500 /46.07 + 0.602 x 2.45 x (78.5 - 25 )

Q = 798.80 Joules

798.80 Joules of heat is required.