Wednesday
September 2, 2015

Homework Help: Chemistry

Posted by Lizichka on Saturday, April 7, 2012 at 6:01pm.

From data below, calculate the total heat (J) needed to convert 0.172 mol of gaseous ethanol (C2H6O) at 351 C and 1 atm to liquid ethanol at 25.0 C and 1 atm.

Boiling point at 1 atm 78.5C
c gas 1.43 J/g C
c liquid 2.45 J/g C
ΔHvap 40.5 kJ/mol

My work:
.172 mol = .003734 g
1) q = mc(T2-T1)= (.003734)(1.43)(351-78.5) = 1.455 J
2) q = n*delta Hvap =.172*40500 = 6966J
3) q = mc(T2-T1) = (.003734)(2.45)(78.5-25) = .4894 J
-------------- adding all the q together gives me -6.97e3 J, its negative since im going from g to l. Its also 3 sig figs. The computer tell me my answer is off by 10%. So what am I doing wrong. Someone please tell me or I will become insane and fail my chem test then drop out of college which will lead me to become homeless, all because of this stupid problem!

Answer this Question

First Name:
School Subject:
Answer:

Related Questions

More Related Questions

Members