Engineering Board Exam Reviewer · Chemistry · hard
Calculate H for CH4 + 2 O2 CO2 + 2 H2O(l), given Hf°: CH4 = -74.8 kJ/mol, CO2 = -393.5 kJ/mol, H2O(l) = -285.8 kJ/mol.
- -604.5 kJ
- -1039.9 kJ
- -890.3 kJ
- 890.3 kJ
Answer
C. -890.3 kJ
Solution
H = ΣΔHf(products) − ΣΔHf(reactants) = [-393.5 + 2(-285.8)] - [-74.8 + 0] = -890.3 kJ.
More Chemistry questions
- Given C + O2 CO2, H = -393.5 kJ, how much heat is released when 24 g of carbon burns completely? (C = 12)
- The rate constant of a reaction doubles when the temperature increases from 300 K to 310 K. What is the activation energy? (R = 8.314…
- A common rule of thumb is that the rate of many reactions roughly doubles for every:
- If doubling the concentration of a reactant quadruples the reaction rate, the reaction is:
- If doubling the concentration of a reactant doubles the reaction rate, the reaction is:
- A first-order reaction has a rate constant of 0.0231 min-1. What is its half-life?
- For a first-order reaction, the half-life:
- The K sp of AgCl is 1.8 × 10-10. What is its molar solubility in pure water?
- The molar solubility of a salt MX2 is 1 × 10-4 M. What is its K sp?
- At equilibrium for N2 + 3 H2 2 NH3, the concentrations are [ N2] = 0.2 M, [ H2] = 0.6 M and [ NH3] = 0.4 M. What is Kc?