Monday

April 21, 2014

April 21, 2014

Total # Posts: 13

**Thermochemistry**

The standard enthalpy of formation of n-octane is -249.95 kJ/mol. Compute the amount of heat liberated when 5.24 g of n-octane is burned completely with excess oxygen to form carbon dioxide and liquid water.

**Thermochemistry**

A constant pressure calorimeter having a heat capacity of 60.8 kJ/K is used to measure the energy released from burning a compound in excess oxygen to form CO2(g) and H2O(l). If the enthalpy of combustion of the compound is -2914.0 kJ/mol and the temperature of the calorimeter...

**Thermochemistry**

Suppose 23.6 g of ClF3(g) and 40 g of Li(s) are mixed and allowed to react at atmospheric pressure and 25 C until one of the reactants is used up, producing LiCl(s) and LiF(s). Using the NIST value for the enthalpy of formation of ClF3 (webbook.nist.gov), calculate the enthalp...

**Thermochemistry**

Compute the amount of heat released (absolute value) when 2.3 kg of liquid ethanol is burned in excess oxygen to make carbon dioxide and liquid water.

**Chemistry**

A 1.2 g sample of C-5 H-10 O is burned completely in excess oxygen to yield CO2(g) and H2O(l) at 25 C, releasing 43.52 kJ of energy. What is the enthalpy of formation of C-5 H-10 O?

**Chemistry**

Calculate the volume of natural gas (methane) required to bring 3.9 L of water to a boil. Assume the initial temperature of the water is 39 C, and the methane is at 1 bar and 25 C. Assume that methane is an ideal gas, the specific heat capacity of water to be constant and equ...

**Thermochemistry**

Compute the change in temperature when 1.1 g of sodium chloride is dissolved in 200.0 mL of water initially at 28 C. The heat capacity of water is 4.184 J/mL/K. Neglect the heat capacity of the NaCl. Species ΔfH (kJ/mol) NaCl(aq)-407.3 NaCl(s) -411.2

**Thermochemistry**

If a chalice made of pure gold weighing 1.24 kg and initially at 15 C is filled with 100.0 mL of water at 89 C, what is the final equilibrium temperature of the system? The heat capacities of water and gold are 75.29 and 25.42 J/mol/K, respectively.

**Thermochemistry**

A sample of liquid mercury (mass 58 g and temperature 149.0 C) is poured into 79 g of H2O at 19 C. Calculate the final temperature of the mixture, assuming no heat is lost. The heat capacities of Hg and H2O are 27.98 and 75.33 J/mol/K, respectively.

**ThermoChemistry**

Calculate the final temperature of solution when 10 g of oxalic acid, (COOH)2(s), is dissolved in 110.0 mL of water that is initially at 26 C. The enthalpies of formation of oxalic acid in the solid and aqueous phases are -826.8 and -818.8 kJ/mol, respectively. The heat capaci...

**ThermoChemistry**

If 18 g of Kr initially at 0.5 bar and 18 L is brought to 0.49 bar and 5L, what is the overall change in enthalpy of this process? Assume that Kr is an ideal gas.

**ThermoChemistry**

When 19 mL of water at 22 C is combined with 18 mL of water at 64 C, what is the final temperature of the water?. The specific heat of water is 4.184 J/g/K and its density is 1.0 g/mL.

**Chemistry**

The enthalpy of dissociation for hydrogen H2(g) → 2 H(g) is ΔH = 436.0 kJ/mol. What is the difference between the bond enthalpy (ΔH) and bond energy (ΔE) for this process under standard conditions at 298.15 K?

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