Solution



Back 		Step 1
Required:

Step 2
Write out given information in equation form.
Equation 1
( = 233 kJ)
Equation 2
 (= 114.5 kJ)
Equation3
 ( = 194.5 kJ)

Step 3
Rearrange
Equation 1 (Reverse)
(= -233 kJ)
Equation 2 (Reverse)
( = -114.5 kJ)
Equation3 (1)
( = 194.5 kJ)

( = - 153 kJ)