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Practice with Hess's Law and Standard Heats of Formation 1. (Example) The reaction C He(g) +...
Practice with Hess's Law and Standard Heats of Formation 1. (Example) The reaction C2H4 (g) + 6 F2 (g) → 2 CF4(g) + 4 HF (g) can be written as the sum of: C2H4 (9) ► 2 C(s) + 2 H2 (g) AH = -52.3 kJ/mol 2 C(s) + 4 F2 (9) ► 2 CF4(9) AH = -1360 kJ/mol 2 H2(g) + 2 F2 (g) → 4 HF (a) AH = -1074 kJ/mol C2H4(g) + 6 F2(g) → 2 CF4(g)...
5. Using standard heats of formation, calculate AH for 4 FeO (s) + O2(g) → 2 Fe2O3 (s) AH1 of FeO (s) = -272.0 kJ/mol AHºf of Fe2O3 (s) = -825.5 kJ/mol 3. Given 3 C (s) + 4 H2(g) → C3H8 (9) AH = -103.85 kJ/mol C(s) + O2(g) + CO2(g) AH = -393.5 kJ/mol H2 (g) + 12 O2(g) → H2O (1) AH = -285.8 kJ/mol find AH for C3H8 (g) + 5 O2(g) → 3 CO2 (g)...
Hess's Law Practice Find AH° for the following equation: SiO2(s) + 4HF(g) → SiF4(g) + 2H2O(g) Using the following equations: Si(s) + O2(g) → SiO2(s) Si(s) + 2F2(g) → SiF4(g) H2(g) + F2(g) → 2HF(g) H2(g) + 4202(g) → H2O(g) AH = -910.9 kJ/mol rxn AH = -1651 kJ/mol rxn AH = -542 kJ/mol rxn AH = -241.8 kJ/mol rxn
2. Calculate AH for the reaction of ethylene with F2. CHA(g) + 6 F2(g) → 2 CF.(g) + 4 HF(g) using the following enthalpies of reaction: 2 H2(g) + 2 F2(g) → 4 HF(g) AH, = -1074 kJ C(s) + 2 F2(g) → CF4(g) AH2 = -680 kJ C(s) + H2(g) → CH.(g) AH, = 26.2 kJ
Calculate the standard enthalpy of formation of gaseous carbon tetrafluoride (CF4) using the following thermochemical information: Calculate the standard enthalpy of formation of gaseous carbon tetrafluoride (CF4) using the following thermochemical information: H2(g)F2(g) 2 HF(g) 2 CF4(g)4 HF(g) C2H4(g) +6 F2(g) C2H4(g)2 C(s) 2 H2(g) AH -537 kJ AH 2486.3 kJ AH -52.3 kJ ΔΗ - kJ
6. Hess's Law. Use the data in Table 1 to calculate AH for the reaction below: Table 1. Change in Enthalpy for Reactions Reactions Change in Enthalpy (AH) AH = -393.5 kJ/mol (1) C() (2) Hz((g) + + O2(g) O2(g) → CO2(8) → H2O(l) AH2 = -285.8 kJ/mol (3) 2CH.(g) + 702(g) → 4 CO2(g)+ 6H2O(1) AH = -283.0 kJ/mol Calculate the enthalpy change for the reaction: 2 C(s) + 3H2(g) → CzH6(g) AH = kJ/mol
6. Hess's Law. Use the data in Table 1 to calculate AH for the reaction below: Table 1. Change in Enthalpy for Reactions Reactions Change in Enthalpy (AH) AH = -393.5 kJ/mol (1) C() (2) Hz((g) + + O2(g) O2(g) → CO2(8) → H2O(l) AH2 = -285.8 kJ/mol (3) 2CH.(g) + 702(g) → 4 CO2(g)+ 6H2O(1) AH = -283.0 kJ/mol Calculate the enthalpy change for the reaction: 2 C(s) + 3H2(g) → CzH6(g) AH = kJ/mol
PROBLEM-SOLVING CLASS ACTIVITY 11 Use Hess's Law to calculate the enthalpy of formation of CH2OH: C(graphite) + 2 H2(g) + 1026) → CH2OH(1) Given the following data: CH2OH() • 02(9) + CO2(g) + 2H2O(1) AH°: -726.4 kJ/mol C(graphite). O2(g) → CO2(9) AH' = -393.5 kJ/mol H2(g) + 40269) → H2O(1) AH = -285.8 kJ/mol
Recitation Exercise 9 CHEM 1411 Name Partners Instructor Day of Week 1. Given the equations: N2(g) + O2(g) → 2NO(g) AH = +180.7 kJ 2NO(g) + O2(g) → 2NO2(g) AH =-113.1 kJ 2N20(g) → 2N2(g) + O2(g) AH = -163.2 kJ Calculate the change in enthalpy for the reaction: N2O(g) + NO2(g) → NO(g) 2. An electron in a carbon atom makes a transition from n=2 to n=3. a) Does this transition require energy or emit energy? b) Can you...
Calculate the standard enthalpy of formation of gaseous carbon tetrafluoride (CF4) using the following thermochemical information: 2 HF(g) H2(g) + F2(g) H = +537 kJ 2 CF4(g) + 4 HF(g) C2H4(g) + 6 F2(g) H = +2486.3 kJ C2H4(g) 2 C(s) + 2 H2(g) H = -52.3 kJ Calculate the standard enthalpy of formation of gaseous carbon tetrafluoride (CF4) using the following thermochemical information: 2 HF(g) H2(g) + F2(g) H = +537 kJ 2 CF4(g) + 4 HF(g) C2H4(g) +...