Question

Use the data below to determine the standard molar enthalpy of formation of B2H6 (g). 4B(s)...

Use the data below to determine the standard molar enthalpy of formation of B2H6 (g).

4B(s) + 3 O2(g) --> 2 B2O3................................deltaHrxn= -2543.9 kj/mol

H2(g) + 1/2 O2(g) --> H2O(g).............................deltaHrxn= -241.8 kj/mol

B2H6(g) + O2(g) --> B2O3(s) + 3 H2O(g)..........deltaHrxn= -2032.9kj/mol

Homework Answers

Answer #1

B2H6(g) + O2(g) --> B2O3(s) + 3 H2O(g)..........deltaHrxn= -2032.9kj/mol

To find the ΔHreactiono, use the formula for the standard enthalpy change of formation:

ΔHoreaction=∑ΔHof(products)−∑ΔHof(Reactants)

The relevant standard enthalpy of formation values are:

  • O2(g): 0 kJ/mol
  • H2O(g): -241.8 kJ/mol
  • B2O3(s): -2543.9kJ/mol

Putting these values into the formula above gives the following:

ΔHoreaction= (1mol)(-2543.9 kJ/mol + 3* -241.8)−[(1mol)(X kJ/mol)+(0mol kJ/mol]

-2032.9kj/mol = (-3269.3kj/mol) − X

standard molar enthalpy of formation of B2H6 (g) = −1236. 4 kJ/mol

Know the answer?
Your Answer:

Post as a guest

Your Name:

What's your source?

Earn Coins

Coins can be redeemed for fabulous gifts.

Not the answer you're looking for?
Ask your own homework help question
Similar Questions
1.) Using enthalpies of formation, calculate the standard change in enthalpy for the thermite reaction. The...
1.) Using enthalpies of formation, calculate the standard change in enthalpy for the thermite reaction. The enthalpy of formation of Fe3O4 is −1117 kJ/mol. 8 Al(s) + 3 Fe3O4(s) → 4 Al2O3(s) + 9 Fe(s) 2. a) Nitroglycerin is a powerful explosive, giving four different gases when detonated. 2 C3H5(NO3)3(l) → 3 N2(g) + 1/2 O2 (g) + 6 CO2(g) + 5 H2O(g) Given that the enthalpy of formation of nitroglycerin, ΔHf°, is −364 kJ/mol, calculate the energy (heat at...
Calculate the standard enthalpy of formation of liquid water (H2O) using the following thermochemical information: 4...
Calculate the standard enthalpy of formation of liquid water (H2O) using the following thermochemical information: 4 B(s) + 3 O2(g) 2 B2O3(s) H = -2509.1 kJ B2H6(g) + 3 O2(g) B2O3(s) + 3 H2O(l) H = -2147.5 kJ B2H6(g) 2 B(s) + 3 H2(g) H = -35.4 kJ
The standard molar enthalpy of formation, of diborane cannot be determined directly because the compound cannot...
The standard molar enthalpy of formation, of diborane cannot be determined directly because the compound cannot be prepared by reaction of boron and hydrogen. However, the value can be calculated. Calculate the standard enthalpy of formation of gaseous diborane(B2H6) using the following thermochemical information: i) 4B(s) + 3O2(g) --> WB2O3(S) = -2509.1kJ ii) 2H2(g) + O2(g) --> 2H2O(l) = - 571.7kJ iii) B2H6(g) + 3O2(g) --> B2O3(s) + 3H2O(l) = -2147.5 kJ
The standard molar enthalpy of formation for gaseous H2O is −241.8 kJ/mol. What is the standard...
The standard molar enthalpy of formation for gaseous H2O is −241.8 kJ/mol. What is the standard molar enthalpy of formation for liquid hydrazine (N2H4)?      N2H4(l) + O2(g) → N2(g) + 2H2O(g)      ΔH° = ‒534.2 kJ    ‒292 kJ/mol     292 kJ/mol     ‒146 kJ/mol 50.6 kJ/mol ‒50.6 kJ/mol
9. Use the following experimentally derived combustion data to calculate the standard molar enthalpy of formation...
9. Use the following experimentally derived combustion data to calculate the standard molar enthalpy of formation (ΔH°f ) of liquid methanol (CH3OH) from its elements. 2 CH3OH(l) + 3 O2(g) → 2 CO2(g) + 4 H2O(l)     ΔH°rxn = −1452.8 kJ C(graphite) + O2(g) → CO2(g)                               ΔH°rxn = −393.5 kJ 2 H2(g) + O2(g) → 2 H2O(l)                                     ΔH°rxn = −571.6 kJ (1) −238.7 kJ/mol    (2) 487.7 kJ/mol       (3) −548.3 kJ/mol    (4) 20.1 kJ/mol         (5) 47.1 kJ/mol
The standard enthalpy change for the combustion of 1 mole of ethylene is -1303.1 kJ C2H4(g)...
The standard enthalpy change for the combustion of 1 mole of ethylene is -1303.1 kJ C2H4(g) + 3 O2(g) ----> 2 CO2(g) + 2 H2O Calculate the change of Hf for ethylene based on the following standard molar enthalpies of formation. molecules Change in Hf (kJ/mol) CO2 -393.5 H2O -241.8
Given the following information below, use Hess’s Law to calculate the enthalpy of formation for sodium...
Given the following information below, use Hess’s Law to calculate the enthalpy of formation for sodium oxide: Na (s)     +      HCl (l)  à    NaCl (aq) + ½ H2 (g)                ∆HRx = -393.1 kJ/mol Na2O (s)     +     2 HCl (l)  à 2 NaCl (aq)   + H2O              ∆HRx = -675.2 kJ/mol H2 (g)       +      ½ O2 (g)  à    H2O (g)                              ∆HRx = -288.1 kJ/mol 2 Na (s)       +       ½ O2 (g)   à   Na2O (s)                          ∆HRx =    __________ kJ/mol Calculated Heat of Reaction is....? (Put your answer in...
Use tabulated standard molar enthalpy changes of formation to calculate Delta H rxn for the following...
Use tabulated standard molar enthalpy changes of formation to calculate Delta H rxn for the following (unbalanced) reactions: SHOW WORK a. N2O4 (g) + H2 (g) --> N2 (g) + H2O(g) b. H2S (g) + O2 (g) --> SO2 (g) + H2O(g) c. Fe2O3 (s) + HCl(g) --> FeCl3 (s) + H2O(g)
Find ΔH° for the formation of solid vanillin, C8H8O3(s), using the data below. C(s) + O2(g)...
Find ΔH° for the formation of solid vanillin, C8H8O3(s), using the data below. C(s) + O2(g) → CO2(g) ΔH°= -393.52 kJ/mol H2(g) + ½O2(g) → H2O(l) ΔH°= -285.83 kJ/mol C8H8O3(s) + 8½O2(g) → 8CO2(g) + 4H2O(l) ΔH°= -3827.88 kJ/mol The heat of formation of solid vanillin is _______Kj mol-1
Given the following reactions and their associated enthalpy changes    CO2 (g) →      C (s) +...
Given the following reactions and their associated enthalpy changes    CO2 (g) →      C (s) + O2 (g)                          ΔH = 393.5 kJ C3H8 (g) + 5 O2 (g) →     3 CO2 (g) + 4 H2O (g)   ΔH = -2044 kJ     H2 (g) + 1/2 O2 (g) →        H2O (g)                     ΔH = -241.8 kJ calculate the enthalpy change for the following reaction: 4 H2 (g) + 3 C (s)→ C3H8 (g)