Question

please show me how to get the correct answers in preperation for my upcoming exam

14.) A 15.) B

14. Given: 2 Al(s) + 3/2 O2(g) - Al2O3(s) Hºe - -1670 kJ for Al2O3(s) What is AH for the following reaction? 2 A1,0, (s) - 4 Al(s) + 3 O2(g) Hºrn - ? A. 3340 kJ B. 1670 kJ C. -3340 kJ D. -1670 kJ E . -835 kJ 15. Given the following thermochemical equation: 2 SO2(g) + O2(g) - 2 so, (g) Hºrxn--198 kJ How much heat is evolved when 600 g of SO2 is burned? A. 5.46 x 10-2 kJ B. 928 kJc. 1.85 x 103 kJ D. 59400 kJ E. 3.71 x 103 kJ

Answer 1

1 2 Al(s) + 3%021 - ALO3 -0 - DH4 = -1670 kJ for Al₂Oz AH, = 4A4 product-{AGH Reactants = - 1670 (-0) [DH = -167 KJ] *DHT0 O₂ and Al are elemental State of these. In elemental state (naturally occurring state enthalpy of formation is always sero). М

2xReversing © ; reversing @ and amuling by 2; we get; 2Al₂O 4A1+302 .. AH = (-AHo) x2 = (+1670) x2 DH = 3340 kJ I Thuis, enthalpy change can be calculated by searranging the equations using the concept of stess law O to 2503 DH = - 198 kJ : 2 mde Soz burning produces -198 KJ heat i Imol. 1 1.99 kJ heat molar mass of 50 2= 64 g/mol 64g produces 99 KJ heat 600g will foroduce 99 x 600 kJ 64 3-928. 125 KJ it is a combustion process heat is evolved. i Heat = 928 kJ | Thus, heat evolved is 928 kJ