Question

Question 2 3 pts The heat of fusion for glycerol (C3H803) is 18.48 kJ/mol. How much heat would be absorbed when 227.57 g of glycerol undergo fusion? Express your answer in units of kilojoules (kJ) using at least three significant figures. Question 3 3 pts The Arxn for the combustion of acetone (C3HO) is -895 kJ, as shown below. How many grams of Oz would need to be consumed by this reaction in order to release 571.9 kJ of heat? Express your answer in units of grams using at least three significant figures. + 3 CO2 (g) + 3 H20 C3H60 (1) + 4 O2(g) (1) AHxn = -895 kJ

Answer 1

2)

Molar mass of C3H8O3,

MM = 3*MM(C) + 8*MM(H) + 3*MM(O)

= 3*12.01 + 8*1.008 + 3*16.0

= 92.094 g/mol

mass(C3H8O3)= 227.57 g

use:

number of mol of C3H8O3,

n = mass of C3H8O3/molar mass of C3H8O3

=(2.276*10^2 g)/(92.09 g/mol)

= 2.471 mol

Now use:

Q = number of mol * HFusion

= 2.471 mol * 18.48 KJ/mol

= 45.66 KJ

Answer: 45.66 KJ

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