sys Example: Calculate the AG˚ve for N₂+ 3H2 → 2NH3 at 25°C and 225°C S° N2(g) 191.5 J/mol K = S° H2(g) = 130.6 J/mol K = S° NH3(g) 192.5 J/mol K o AH, N2(g) = 0 kJ/mol • AH H2(g) = 0 kJ/mol • AH NH3(g) = -46.19 kJ/mol = AG sys AH sys - TAS sys

Given: 2Cu2O(s) + O2(g) 4CuO(s)H = 288 kJ Cu2O(s) CuO(s) + CuO(s)H = 11kJ Calculate the standard enthalpy of formation (Ht) for CuO(s).

In a coffee-cup calorimeter, 150.0 mL of 0.50 M HCI is added to 50.0 mL of 1.00 M NaOH to make 200.0 g solution at an initial temperature of 48.2C. If the enthalpy of neutralization for the reaction between a strong acid and a strong base is 56 kJ/mol, calculate the final temperature of the calorimeter contents. Assume the specific heat capacity of the solution is 4.184 J/g C and assume no heat Joss to the surroundings.

Give the definition of the standard enthalpy of formation for a substance. Write separate reactions for the formation of NaCl, H2O , C6H12O6, and PbSO4 that have H values equal to Hf for each compound.

An industrial process for manufacturing sulfuric acid, H2SO4, uses hydrogen sulfide, H2S, from the purification of natural gas. In the first step of this process, the hydrogen sulfide is burned to obtain sulfur dioxide, SO2. 2H2S(g)+3O2(g)2H2O(l)+2SO2(g);H=1124kJ The density of sulfur dioxide at 25C and 1.00 atm is 2.62 g/L, and the molar heat capacity is 30.2 J/(mol C). (a) How much heat would be evolved in producing 1.00 L of SO2 at 25C and 1.00 atm? (b) Suppose heat from this reaction is used to heat 1.00 L of the SO2 from 25C to 500C for its use in the next step of the process. What percentage of the heat evolved is required for this?

Gas A2 reacts with gas B2 to form gas AB at a constant temperature. The bond energy of AB is much greater than that of either reactant. What can be said about the sign of H? SSurr? S? Explain how potential energy changes for this process. Explain how random kinetic energy changes during the process.

Dissolving 6.00 g CaCl2 in 300 mL of water causes the temperature of the solution to increase by 3.43 C. Assume that the specific heat of the solution is 4.18 J/g K and its mass is 306 g. (a) Calculate the enthalpy change when the CaCl2 dissolves. Is the process exothermic or endothermic? (b) Determine H on a molar basis for CaCl2(s)H2OCa2+(aq)+2Cl(aq)

At 298 K, the standard enthalpies of formation for C2H2(g) and C6H6(l) are 227 kJ/mol and 49 kJ/mol, respectively. a. Calculate H for C6H6(l)3C2H2(g) b. Both acetylene (C2H2) and benzene (C6H6) can be used as fuels. Which compound would liberate more energy per gram when combusted in air?

A substance, X, has the following properties: Specific Heat Capacities Hvap 20.kj/mol C(s) 3.0j/gC Hfus 5.0kj/mol C(l) 2.5j/gC bp 75C C(g) 2.5j/gC mp 15C

The process of dissolving ammonium nitrate, NH4NO3, in water is an endothermic process. What is the sign of q? If you were to add some ammonium nitrate to water in a flask, would you expect the flask to feel warm or cool?