Calculate ΔHrxn from standard enthalpies of formation
\iven the following reaction and standard enthalpy values, find ΔHrxn:
2H2(g)+O2(g)→2H2O(l)
ΔH°f [H₂O(l)] = −285.8 kJ/mol
ΔH°f [H₂(g)] = 0
ΔH°f [O₂(g)] = 0
ΔHrxn = -571.6 kJ
Use the average bond energies on the CH122 equation sheet to estimate
the ΔHrxn for the following reaction:
a. N2 + 3 H2 → 2 NH3
Hrxn = -86 kJ/mol
Consider the following reaction:
2 NO2 (g) ➝ N2O4 (g) ΔHrxn: -57.23 kJ/mol
What mass of NO2 must react for the reaction to release 450.0 kJ of heat?
723.55 g NO2
A system that absorbs 562 J of heat and has 23 J of work done on it
585 J
How much heat is produced when 100 mL of 0.250 M HCl (density, 1.00 g/mL) and 200 mL of 0.150 M NaOH (density, 1.00 g/mL) are mixed?
HCl (aq) + NaOH (aq) --> NaCl (aq) + H2O (l)
ΔH = - 58 kJ/mol
-1.45 kJ
Calculate Hrxn:
CH4(g)+2O2(g)→CO2(g)+2H2O(g)
Given:
ΔH°f [CH₄(g)] = −74.8 kJ/mol
ΔH°f [CO₂(g)] = −393.5 kJ/mol
ΔH°f [H₂O(g)] = −241.8 kJ/mol
ΔH°f [O₂(g)] = 0
-802.3 kJ
Use the average bond energies on the CH122 equation sheet to estimate the ΔHrxn for the following reactions:
2 H2O → 2 H2 + O2
Hrxn = +486 kJ/mol
C2H4(g) + H2(g) → C2H6(g) ΔH=−137 kJ
Question:
What mass of C₂H₆ is produced when 411 kJ of heat is released?
90.2 g
A system that releases 84 J of heat and has 496 J of work done on it
412 J
C2H4 + 6F2 ⟶ 2CF4 + 4HF
Find the △H of the above reaction given:
H2 + F2 ⟶ 2HF △H = -537 kJ
2C + 2H2 ⟶ C2H4 △H = +52 kJ
CF4 ⟶ C + 2F2 △H = +680 kJ
-2486 kJ
Find Hrxn:
2Al(s)+Fe2O3(s)→Al2O3(s)+2Fe(s)
Given:
ΔH°f [Al₂O₃(s)] = −1675.7 kJ/mol
ΔH°f [Fe₂O₃(s)] = −824.2 kJ/mol
ΔH°f [Al(s)] = 0
ΔH°f [Fe(s)] = 0
-851.5 kJ
Use the average bond energies on the CH122 equation sheet to estimate the ΔHrxn for the following reactions:
CH4 + H2O → CO + 3 H2
Hrxn = +200 kJ/mol
Calculate Hrxn from the following equation:
2SO2(g) + O2(g) → 2SO3(g) ΔH=−198 kJ
Given:
25.0 g SO₂
10.0 g O₂
Hrxn = -38.61 kJ
A system that absorbs 512 J of heat and does 715 J of work
-203 J