• Question 01:

    The combustion of methane occurs according to the equation, and with the enthalpy change, shown below. What is the energy change when 0.080 g of methane is completely combusted in oxygen gas?

    CH4(g) + 2O2(g) → CO2(g) + 2H2O(l) ΔH = - 890 kJ molrxn-1

  • Question 02:

    In a chemical reaction where the products have a higher enthalpy than the reactants, which terms best describe the ∆H for the reaction?

  • Questions 03-05:

    Questions 3-5 relate to the following lab situation.

    An experiment is conducted by completely dissolving a sample of an ionic compound in distilled water. When the solid had completely dissolved, the temperature of the solution was found to have decreased when compared to the initial temperature of the distilled water.

    Question 03:

    Which of the following statements accurately describes the changes that occur in this reaction?

  • Question 04:

    In addition to the initial temperature of the water, what other data would be required in order to calculate a value for the ∆Hsolution in units of kJmol-1? (You may assume that the molar mass of the ionic solid is known).

  • Question 05:

    If the solid had been refrigerated rather than being at room temperature prior to being added to the water, what effect would this have on the calculated value for ∆Hsolution?

  • Question 06:

    The chemical equation for the standard enthalpy of combustion of which of the following, is also a chemical equation that represents a standard enthalpy of formation?

  • Question 07:

    Calculate the enthalpy change in the reaction below using the bond energies given.

    CH4(g) + 4Cl2(g) → 4HCl(g) + CCl4(g)

    C-H = 414 kJ, Cl-Cl = 200 kJ, H-Cl = 432 kJ, C-Cl = 397 kJ

  • Question 08:

    When using a Born-Haber cycle in order to calculate a value for the standard enthalpy of formation of MgCl2(s), which of the following reactions is irrelevant?

  • Question 09:

    Which of the following is associated with an increase in the energy of the surroundings?

  • Question 10:

    What is the standard enthalpy of formation of butane, C4H10, given the data below?

    ΔH°combustion for C4H10(g) = -2900 kJ mol-1
    ΔH°formation for CO2(g) = -395 kJ mol-1
    ΔH°formation for H2O(l) = -290 kJ mol-1