A considerable amount of heat is required for the decomposition of aluminum oxide. 2Al2O3(s) ? 4Al(s) + 3O2(g) DH = +3352 KJ What is the heat of formation for 1 mole of aluminum oxide from its elements? A) +3352 KJ B) -3352 KJ C) +1676 KJ D) -1676 KJ

1
A considerable amount of heat is required for the
decomposition of aluminum oxide. 2Al2O3(s) ?
4Al(s) 3O2(g) DH 3352 KJWhat is the heat
of formation for 1 mole of aluminum oxide from
its elements?A) 3352 KJB) -3352 KJC) 1676
KJD) -1676 KJ
Thursdays Bell Ringer
2
A considerable amount of heat is required for the
decomposition of aluminum oxide. 2Al2O3(s) ?
4Al(s) 3O2(g) DH 3352 KJWhat is the heat
of formation for 1 mole of aluminum oxide from
its elements?A) 3352 KJB) -3352 KJC) 1676
KJD) -1676 KJ
Thursdays Bell Ringer
3
Entropy

• Entropy is a measure of disorder.

LIQUID
GAS
SOLID
Entropy Increases
4
Predicting Changes in Entropy

• For each process or reaction, predict whether
  entropy would increase (I) or decrease (D).
• H2O(s) ? H2O(l)
• 2NH3(g) ? 3H2(g) N2(g)
• CaCl2(aq) Na2CO3(aq) ? CaCO3(s) 2 NaCl(aq)
• 2 Na(s) 2 H2O(l) ? 2 NaOH(aq) H2(g)

I
I
D
I
5
3.20 kcal of heat is added to 1.00 kg of ice at
0C. The heat of fusion of ice is 80 cal/g. How
much ice melts? A) 1.00 kgB) 40.0gC) 25.0
gD) 0.960 kg
Fridays Bell Ringer
6
3.20 kcal of heat is added to 1.00 kg of ice at
0C. The heat of fusion of ice is 80 cal/g. How
much ice melts? A) 1.00 kgB) 40.0gC) 25.0
gD) 0.960 kg
Fridays Bell Ringer