5.3 Enthalpy  (Page 11/25)

How much heat is produced when 100 mL of 0.250 M HCl (density, 1.00 g/mL) and 200 mL of 0.150 M NaOH (density, 1.00 g/mL) are mixed?
$\text{HCl}\left(aq\right)+\text{NaOH}\left(aq\right)⟶\text{NaCl}\left(aq\right)+{\text{H}}_2\text{O}\left(l\right)\text{Δ}{H}_{298}^{°}=\mathrm{-58}\text{kJ}$

If both solutions are at the same temperature and the heat capacity of the products is 4.19 J/g °C, how much will the temperature increase? What assumption did you make in your calculation?

A sample of 0.562 g of carbon is burned in oxygen in a bomb calorimeter, producing carbon dioxide. Assume both the reactants and products are under standard state conditions, and that the heat released is directly proportional to the enthalpy of combustion of graphite. The temperature of the calorimeter increases from 26.74 °C to 27.93 °C. What is the heat capacity of the calorimeter and its contents?

Before the introduction of chlorofluorocarbons, sulfur dioxide (enthalpy of vaporization, 6.00 kcal/mol) was used in household refrigerators. What mass of SO ₂ must be evaporated to remove as much heat as evaporation of 1.00 kg of CCl ₂ F ₂ (enthalpy of vaporization is 17.4 kJ/mol)?

The vaporization reactions for SO ₂ and CCl ₂ F ₂ are ${\text{SO}}_2(l)⟶{\text{SO}}_2(g)$ and ${\text{CCl}}_2\text{F}\left(l\right)⟶{\text{CCl}}_2{\text{F}}_2(g),$ respectively.

Homes may be heated by pumping hot water through radiators. What mass of water will provide the same amount of heat when cooled from 95.0 to 35.0 °C, as the heat provided when 100 g of steam is cooled from 110 °C to 100 °C.

Which of the enthalpies of combustion in [link] the table are also standard enthalpies of formation?

Does the standard enthalpy of formation of H ₂ O( g ) differ from Δ H ° for the reaction ${\text{2H}}_2(g)+{\text{O}}_2(g)⟶2{\text{H}}_2\text{O}\left(g\right)?$

Joseph Priestly prepared oxygen in 1774 by heating red mercury(II) oxide with sunlight focused through a lens. How much heat is required to decompose exactly 1 mole of red HgO( s ) to Hg( l ) and O ₂ ( g ) under standard conditions?

How many kilojoules of heat will be released when exactly 1 mole of manganese, Mn, is burned to form Mn ₃ O ₄ ( s ) at standard state conditions?

How many kilojoules of heat will be released when exactly 1 mole of iron, Fe, is burned to form Fe ₂ O ₃ ( s ) at standard state conditions?

The following sequence of reactions occurs in the commercial production of aqueous nitric acid:
$4{\text{NH}}_3(g)+5{\text{O}}_2(g)⟶4\text{NO}\left(g\right)+6{\text{H}}_2\text{O}\left(l\right)\text{Δ}\text{H}=\mathrm{-907}\text{kJ}$
$2\text{NO}\left(g\right)+{\text{O}}_2(g)⟶2{\text{NO}}_2(g)\text{Δ}\text{H}=\mathrm{-113}\text{kJ}$
$3{\text{NO}}_2+{\text{H}}_2\text{O}\left(l\right)⟶2{\text{HNO}}_3(aq)+\text{NO}(g)\text{Δ}\text{H}=\mathrm{-139}\text{kJ}$

Determine the total energy change for the production of one mole of aqueous nitric acid by this process.

Both graphite and diamond burn.
$\text{C}\left(s,\text{diamond}\right)+{\text{O}}_2(g)⟶{\text{CO}}_2(g)$

For the conversion of graphite to diamond:
$\text{C}\left(s,\text{graphite}\right)⟶\text{C}\left(s,\text{diamond}\right)\text{Δ}{H}_{298}^{°}=1.90\text{kJ}$

Which produces more heat, the combustion of graphite or the combustion of diamond?

From the molar heats of formation in Appendix G , determine how much heat is required to evaporate one mole of water: ${\text{H}}_2\text{O}\left(l\right)⟶{\text{H}}_2\text{O}\left(g\right)$

Which produces more heat?
$\text{Os}\left(s\right)⟶2{\text{O}}_2(g)⟶{\text{OsO}}_4(s)$
or
$\text{Os}\left(s\right)⟶2{\text{O}}_2(g)⟶{\text{OsO}}_4(g)$

for the phase change ${\text{OsO}}_4(s)⟶{\text{OsO}}_4(g)\text{Δ}\text{H}=56.4\text{kJ}$

Calculate $\text{Δ}{H}_{298}^{°}$ for the process
$\text{Sb}\left(s\right)+\frac{5}{2}{\text{Cl}}_2(g)⟶{\text{SbCl}}_5(g)$

from the following information:
$\begin{array}{l}\\ \text{Sb}\left(s\right)+\frac{3}{2}{\text{Cl}}_2(g)⟶{\text{SbCl}}_3(g)\text{Δ}{H}_{298}^{°}=\mathrm{-314}\text{kJ}\\ {\text{SbCl}}_3(s)+{\text{Cl}}_2(g)⟶{\text{SbCl}}_5(g)\text{Δ}{H}_{298}^{°}=\mathrm{-80}\text{kJ}\end{array}$