Pure Benzene (C6H6) has a melting point of 5.5 degrees C. Delta Hof fusion for b

Question

Pure Benzene (C6H6) has a melting point of 5.5 degrees C. Delta Hof fusion for benzene is 9.87 kj/mol; specific heat for liquidbenzene is 1.63 J/g X degrees).
A. Calculate the number of joules required to melt 57.4 g ofbenzene at 5.5 degrees C.
B. Calculate the number of joules required to raise the temperatureof 57.4 g of liquid benzene from 5.5 degrees C. to 45.0 degreesC.
I got stuck in terms of caculations because I assume you need touse the formula q=s x Delta TX grams of benzene. For part A i got4.0 x10^4 joules and for B I got 3.7 x 10^3 joules. I am not sureis those answers are right but if anyone could help me I wouldreally appreciate it.

Explanation / Answer

A) Simply find the number of moles of beneze and multiply by theheat of fusion. The heat of fusion is the amount of energy requiredto melt a substance. (57.4 g/78 g/mol)(9.87 kJ/mol) = 7.26 kJ = 7260 J B) Use the equation for specific heat. q = mcT q = (57.4 g)(1.63 J/goC)(45.0-5.5) q = 3696 J

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