Energy cycles in reactions

Given the following data: $\ce{CaO(s) + CO2(g) -> CaCO3(s)}$ $\Delta H = -p\ \mathrm{kJ}$ $\ce{2Ca(s) + O2(g) -> 2CaO(s)}$ $\Delta H = -q\ \mathrm{kJ}$ $\ce{2CaCO3(s) -> 2Ca(s) + 2C(s) + 3O2(g)}$ $\Delta H = +r\ \mathrm{kJ}$ What is the $\Delta H$ of the…

Suppose carbonyl dibromide were made by a free-radical chain reaction of carbon monoxide, $\ce{CO}$, with bromine vapour, $\ce{Br2}$, started by ultraviolet light. The questions below treat this hypothetical route with the bond-enthalpy model and the entropy…

Magnesium carbonate and magnesium chloride are ionic compounds. (i) The Born-Haber cycle for magnesium chloride, $\ce{MgCl2}$, is shown with three boxes left empty. Annotate the cycle by writing the name of the process, or the formulas of the species present…

(i) Calculate, in $\mathrm{kJ\,mol^{-1}}$, the standard enthalpy change of this hydrogenation reaction using the enthalpy of combustion data in section 14 of the data booklet. (ii) The standard entropy change for this reaction is…

trans-But-2-ene reacts with hydrogen in the presence of a nickel catalyst to form butane. $\ce{C4H8(g) + H2(g) -> C4H10(g)}$ (i) Calculate, in kJ, the enthalpy change of this reaction from the bond enthalpies in section 12 of the data booklet. (ii) Calculate,…

(i) Outline two advantages of using biobutanol rather than petrol (gasoline) as a fuel for vehicles. (ii) Calculate, using the average bond enthalpies in section 12 of the data booklet, the enthalpy change in $\mathrm{kJ\,mol^{-1}}$ for the combustion of…

Calculate the rise in temperature of 400.0 $\mathrm{cm^3}$ of water heated by the complete combustion of 2.00 g of butan-1-ol, assuming that all the energy released is transferred to the water. Use sections 2 and 14 of the data booklet.

Which equation represents both the standard enthalpy of formation, $\Delta H_\mathrm{f}^\ominus$, of a compound and the standard enthalpy of combustion, $\Delta H_\mathrm{c}^\ominus$, of an element? A. $\ce{C(s) + 1/2 O2(g) -> CO(g)}$ B.…

The diagram shows an energy cycle for the formation of solid potassium bromide from its elements. Which energy change in the cycle represents the first ionization energy of potassium? A. $\Delta H_2$ B. $\Delta H_4$ C. $\Delta H_5$ D. $\Delta H_6$

The table shows standard enthalpies of combustion. Substance $\Delta H_\mathrm{c}^\ominus$ / $\mathrm{kJ\,mol^{-1}}$ $\ce{C4H10(g)}$ −2878 $\ce{C3H6(g)}$ −2058 $\ce{CH4(g)}$ −891 Which expression gives the enthalpy change, in $\mathrm{kJ\,mol^{-1}}$, of the…