The complete combustion of butane gas is a highly exothermic process
releasing 2845kJ of heat per mole of butane. Determine ΔH involved in
the burning of 50.0grams of butane.
(ΔH=-2452kJ)
2H2 + O2  2H2O ΔH=-572kJ
How much heat is released when 2.95grams H2 reacts with excess O2?
(422kJ)
Specific heat-energy(J) needed to raise 1 gram of a substance 1⁰C.
Al
0.89 J/g⁰C
C
0.71 J/g⁰C
Fe
0.45 J/g⁰C
Hg 0.14 J/g⁰C
If the same amount of heat energy is applied to 1.0g of each substance,
which one will reach the highest temp?
(Hg)
35.0grams of unknown metal heated to 75.0⁰C is placed in 250.0mL of
water at 20.0⁰C. The final temperature reached is 20.8⁰C. What is
specific heat of the unk. metal?
(.45J/mol•K)
100.0g of Al at 20.0˚C is placed in contact with 10.0g of Fe at 60.0˚C.
What is the final temperature? (Alsp.ht=0.89J/g˚C, Fesp.ht=0.45J/g˚C)
(21.9⁰C)
50.0mL of 0.1M AgNO3 is mixed with 50.0mL of 0.10M HCl at 25.0˚C.
Calculate the enthalpy in kJ/mol of precipitate formed when the final
temperature reached is 25.8˚C. (density=1.00g/mL and specific
heat=4.18J/g˚C)
(ΔH=-66.9kJ/mol)
H2 + 1/2O2  H2O
ΔH=-286kJ
CO2  C + O2
ΔH=394kJ
2CO2+H2OC2H2 +5/2O2
ΔH=1300kJ
Find ΔH for
C2H2  2C + H2
(-226kJ/mol)
CH3CHO+H2CH3CH2OH ΔH= -17.0kJ/mol
Calculate bond energy for C=O
O-H 111kJ/mol
C-C 83kJ/mol
C-O 84kJ/mol
C-H 99kJ/mol
H-H 104kJ/mol
(173kJ/mol)
Write the equation for the enthalpy of formation for nitrogen dioxide.
1/2N2 + O2 NO2
Which has a non-zero enthalpy of formation?
Na
Hg
H2O
Cl2
(H2O)
Calc. the ΔHrxn
2H2S + 3O2  2H2O + 2SO2
ΔHf˚
-20.0 kJ/mol
-285.8 kJ/mol
-296.8 kJ/mol
H2S
H2O
SO2
(ΔH=-1125kJ)
Fill in table-when spontaneous?
ΔH
+
+
ΔS
ΔG
+
+
(always, low temps, high temps, never)
NH4NO3  NH4+ + NO3ΔHf⁰(kJ/mol)
NH4NO3
-366
NH4+
-133
NO3-205
Calculate ΔH⁰, ΔS⁰, ΔG⁰, spontaneous?
ΔH=28kJ
ΔS=.108kJ
ΔG=-4.18kJ
S⁰(J/mol•K)
151
113
146
spontaneous
CHCl3(s)  CHCl3(l)
ΔH⁰=9.2kJ/mol
What is melting point?
ΔS⁰=43.9J/mol•K
(209K)
For a certain reaction,
ΔH⁰=-13.68kJ/mol and
ΔS⁰=-75.8J/mol•K. What is the ΔG⁰? Will increasing or decreasing the
temperature make the reaction thermodynamically favored? At what
temperature will the reaction become thermodynamically favored?
(ΔG=8.91kJ/mol, decreasing temp, below 180K)
The value of the equilibrium constant is 45 at 298K. At the same
temperature Q=35. Determine the value of ΔG⁰ for the reaction and
show which direction the reaction will move to reach equilibrium.
(ΔG=-9.43kJ/mol, shift right to reach eq.)