The constant pressure molar heat capacity of ammonia, NH3, has been found to vary with temperature according to the relation Cp.m / J K-1 mol-1=a+bT+c/T2 With a = 29.73, b = 25.1 F1F1F1S1F1F1F10 10-3 K-1 and c = -1.55 F1F1F1S1F1F1F10 105 K2. Calculate the value of the constant pressure molar heat capacity at 25.0 °C.

A) 217.6 J K-1 mol-1 B) 29.73 J K-1 mol-1 C) 35.47 J K-1 mol-1 D) 657.2 J K-1 mol-1 A) 217.6 J K-1 mol-1 B) 29.73 J K-1 mol-1 C) 35.47 J K-1 mol-1 D) 657.2 J K-1 mol-1 C

Calculate the expansion work done on the system when exactly 1 mol of solid ammonium chloride, NH4Cl, decomposes completely to yield gaseous ammonia, NH3 and hydrogen chloride, HCl at a temperature of 1250 K. Treat the expansion as irreversible and the gases formed as perfect.

A) -15.4 kJ B) -4.96 kJ C) -16.6 kJ D) -20.8 kJ A) -15.4 kJ B) -4.96 kJ C) -16.6 kJ D) -20.8 kJ

Use the following data to determine the standard enthalpy of reaction at 298 K for the addition of hydrogen chloride, HCl, to ethene, C2H4 C2H4(g) + HCl(g) F1F1F1S1?F1F1F10 C2H5Cl(g) $\begin{array}{lc} & \Delta \$ \mathrm{H}^{\circ}(298 \mathrm{~K}) / \mathrm{kJ} \mathrm{mol}^{-1} \\ \mathrm{C}_{2} \mathrm{H}_{4} \\ & +52.2 \\ \mathrm{HCl} \\ & -92.3 \\ \mathrm{C}_{2} \mathrm{H}_{5} \mathrm{Cl} \\ & -109.8 \end{array}$

A) -34.7 kJ mol-1 B) 149.9 kJ mol-1 C) -69.7 kJ mol-1 D) 254.3 kJ mol-1 A) -34.7 kJ mol-1 B) 149.9 kJ mol-1 C) -69.7 kJ mol-1 D) 254.3 kJ mol-1

Exam 2: The First Law of Thermodynamics

The standard enthalpy of formation of benzoic acid, C₆H₅COOH, is -385 kJ mol^-1 at 298 K. Calculate the standard enthalpy of combustion of benzoic acid at this temperature, given that the standard enthalpy of formation of liquid water, H₂O is -285.8 kJ mol^-1 and gaseous carbon dioxide, CO₂, is -393.51 kJ mol^-1.

Free

(Multiple Choice)

4.8/5

(39)

Question 1

Correct Answer:

Verified

The constant pressure molar heat capacity of ammonia, NH₃, has been found to vary with temperature according to the relation C_p.m / J K^-1 mol^-1=a+bT+c/T² With a = 29.73, b = 25.1  10^-3 K^-1 and c = -1.55  10⁵ K². Calculate the value of the constant pressure molar heat capacity at 25.0 °C.

Free

(Multiple Choice)

4.8/5

(33)

Question 2

Correct Answer:

Verified

Hydrazine, N₂H₄, may be produced by the reaction 2 NH₃(g) + H₂O₂(l)  N₂H₄(l) +H₂O(l) Use the following data for the standard enthalpies of formation at 298 K for the various species to calculate the standard enthalpy of reaction at this temperature. _fH^o / (kJ mol^-1 NH₃(g) -46 H₂O₂(l) -188 N₂H₄(l) +51 H₂O(l) -286

Free

(Multiple Choice)

4.8/5

(28)

Question 3

Correct Answer:

Verified

The mean bond enthalpy of a P-Cl bond is 331 kJ mol^-1 and of a Cl-Cl bond is 242 kJ mol^-at 298 K. If the mean standard enthalpy of atomization of white phosphorus is 315 kJ mol^-1, estimate the standard enthalpy of formation of gaseous phosphorus trichloride, PCl₃, at this temperature.

(Multiple Choice)

4.9/5

(32)

Question 4

The standard enthalpy of formation of methane, CH₄, is -75 kJ mol^-1 at 298.15 K. Calculate the mean bond enthalpy of a H-CH₃ bond, given that, at this temperature, the standard enthalpy of atomization of carbon C(s, graphite)  C(g) Is +717 kJ mol^-1 and the standard bond enthalpy of hydrogen, H₂, is 436 kJ mol^-1.

(Multiple Choice)

4.9/5

(38)

Question 5

The constant pressure molar heat capacity of methane, CH₄, is 35.31 J K^-1 mol^-1 at temperatures close to 298 K. Calculate the enthalpy change when 2.00 mol of methane is heated from a temperature of 278 K to 318 K.

(Multiple Choice)

4.9/5

(33)

Question 6

A sample of liquid butan-1-ol, C₄H₇OH was brought to the boil in an open calorimeter. An electric current of 289 mA from a 12.0 V source was then passed through a resistive heater coil which was immersed in the liquid. The current was allowed to flow for a period of 245 s, during which time the temperature remained constant and 1.416 g of butan-1-ol was found to have evaporated. Calculate the molar enthalpy of vaporization of butan-1-ol.

(Multiple Choice)

4.9/5

(34)

Question 7

The heat capacity of a bomb calorimeter and its contents was measured to be 6.14 kJ K^-1. Calculate the change in temperature when a current of 245 mA from a 12.0 V source was allowed to flow through the electrical heater for a period of 254 s.

(Multiple Choice)

4.8/5

(30)

Question 8

The standard enthalpy of formation of gaseous diborane, B₂H₆, is +31 kJ mol^-1 at 298 K. Use the following data for the molar heat capacities at constant pressure to determine the standard enthalpy of reaction at 450 K. C_p,_m^o / kJ mol^-1 B(s) 12.0 H₂(g) 28.8 B₂H₆(g) 56.4

(Multiple Choice)

4.9/5

(24)

Question 9

When 7.82 g of benzaldehyde, C₆H₅CHO, was burned in a bomb calorimeter at 298.15 K, the heat released was 259.2 kJ. Calculate the enthalpy of combustion of benzaldehyde at this temperature.

(Multiple Choice)

4.8/5

(39)

Question 10

Calculate the expansion work done on the system when exactly 1 mol of solid ammonium chloride, NH₄Cl, decomposes completely to yield gaseous ammonia, NH₃ and hydrogen chloride, HCl at a temperature of 1250 K. Treat the expansion as irreversible and the gases formed as perfect.

(Multiple Choice)

4.8/5

(35)

Question 11

Use the following data to determine the standard enthalpy of reaction at 298 K for the addition of hydrogen chloride, HCl, to ethene, C₂H₄ C₂H₄(g) + HCl(g) ? C₂H₅Cl(g) \Delta\ (298)/ +52.2 -92.3 -109.8

(Multiple Choice)

4.8/5

(41)

Question 12

The constant pressure molar heat capacity of argon is 20.79 J K^-1 mol^-1 at 298 K. Predict the value of the constant volume molar heat capacity of argon at this temperature.

(Multiple Choice)

4.8/5

(35)

Question 13

The constant pressure molar heat capacity of zinc is 25.40 J K^-1 mol^-1 at 298 K. Calculate the constant pressure specific heat capacity of zinc at this temperature.

(Multiple Choice)

4.8/5

(39)

Question 14

In the calibration step of a thermochemistry experiment, a current of 117 mA, from a 24.0 V source was allowed to flow through the electrical heater for 247 s and was found to result in an increase in the temperature of the calorimeter and its contents of +1.25 K. Calculate the heat capacity of the calorimeter and its contents.

(Multiple Choice)

4.9/5

(42)

Question 15

Use the following data to determine the standard enthalpy change for the reaction K(g) + ½Cl₂(g)  K⁺(g) + ½Cl^-(g) at a temperature of 298.15 K. The values refer to standard enthalpy changes at this temperature. Ionization enthalpy of potassium _ionH^o = +418 kJ mol^-1 Enthalpy of formation of atomic chlorine _fH^o = +121 kJ mol^-1 Electron gain enthalpy of atomic chlorine _egH^o = -349 kJ mol^-1

(Multiple Choice)

4.9/5

(31)

Question 16

The constant pressure molar heat capacity of nitrogen gas, N₂, is 29.125 J K^-1 mol^-1 at 298.15 K. Calculate the change in the internal energy when 2.00 mol of nitrogen gas is heated so that its temperature increases by 25.0°C. Assume that the value of the heat capacity does not vary with temperature.

(Multiple Choice)

4.9/5

(35)

Question 17

Calculate the heat transferred to the system when 1.00 mol of a perfect gas expands reversibly at a constant temperature of 25°C so that its volume doubles.

(Multiple Choice)

4.8/5

(33)

Question 18

The molar heat capacity of solid aluminium is 24.4 J K^-1 mol^-1 at 25°C. Calculate the change in internal energy when 1.00 mol of solid aluminium is heated from a temperature of 20°C to 30°C.

(Multiple Choice)

4.7/5

(37)

Question 19

The enthalpy of vaporization of tetrachloromethane, CCl₄, is 30.5 kJ mol^-1 at its normal boiling temperature of 350 K. Estimate the enthalpy of vaporization at 298 K, given that the molar constant pressure heat capacities of liquid and gaseous tetrachloromethane are 83.5 and 135 J K^-1 mol^-1.

(Multiple Choice)

4.8/5

(39)

Question 20

Showing 1 - 20 of 20

The mean bond enthalpy of a P-Cl bond is 331 kJ mol^-1 and of a Cl-Cl bond is 242 kJ mol^-at 298 K. If the mean standard enthalpy of atomization of white phosphorus is 315 kJ mol^-1, estimate the standard enthalpy of formation of gaseous phosphorus trichloride, PCl₃, at this temperature.

The constant pressure molar heat capacity of methane, CH₄, is 35.31 J K^-1 mol^-1 at temperatures close to 298 K. Calculate the enthalpy change when 2.00 mol of methane is heated from a temperature of 278 K to 318 K.

The heat capacity of a bomb calorimeter and its contents was measured to be 6.14 kJ K^-1. Calculate the change in temperature when a current of 245 mA from a 12.0 V source was allowed to flow through the electrical heater for a period of 254 s.

The standard enthalpy of formation of gaseous diborane, B₂H₆, is +31 kJ mol^-1 at 298 K. Use the following data for the molar heat capacities at constant pressure to determine the standard enthalpy of reaction at 450 K. C_p,_m^o / kJ mol^-1 B(s) 12.0 H₂(g) 28.8 B₂H₆(g) 56.4

When 7.82 g of benzaldehyde, C₆H₅CHO, was burned in a bomb calorimeter at 298.15 K, the heat released was 259.2 kJ. Calculate the enthalpy of combustion of benzaldehyde at this temperature.

Calculate the expansion work done on the system when exactly 1 mol of solid ammonium chloride, NH₄Cl, decomposes completely to yield gaseous ammonia, NH₃ and hydrogen chloride, HCl at a temperature of 1250 K. Treat the expansion as irreversible and the gases formed as perfect.

Use the following data to determine the standard enthalpy of reaction at 298 K for the addition of hydrogen chloride, HCl, to ethene, C₂H₄ C₂H₄(g) + HCl(g) ? C₂H₅Cl(g) \Delta\ (298)/ +52.2 -92.3 -109.8

The constant pressure molar heat capacity of argon is 20.79 J K^-1 mol^-1 at 298 K. Predict the value of the constant volume molar heat capacity of argon at this temperature.

The constant pressure molar heat capacity of zinc is 25.40 J K^-1 mol^-1 at 298 K. Calculate the constant pressure specific heat capacity of zinc at this temperature.

Calculate the heat transferred to the system when 1.00 mol of a perfect gas expands reversibly at a constant temperature of 25°C so that its volume doubles.

The molar heat capacity of solid aluminium is 24.4 J K^-1 mol^-1 at 25°C. Calculate the change in internal energy when 1.00 mol of solid aluminium is heated from a temperature of 20°C to 30°C.

The enthalpy of vaporization of tetrachloromethane, CCl₄, is 30.5 kJ mol^-1 at its normal boiling temperature of 350 K. Estimate the enthalpy of vaporization at 298 K, given that the molar constant pressure heat capacities of liquid and gaseous tetrachloromethane are 83.5 and 135 J K^-1 mol^-1.

The Propertiesof Gases

The Second Law of Thermodynamics

Physical Transformations

Chemical Change

Chemical Kinetics

Quantum Theory

Atomic Structure

The Chemical Bond

Molecular Interactions

Molecular Spectroscopy

Statistical Thermodynamics

Filters

Exam 2: The First Law of Thermodynamics

The constant pressure molar heat capacity of ammonia, NH3, has been found to vary with temperature according to the relation Cp.m / J K-1 mol-1=a+bT+c/T2 With a = 29.73, b = 25.1  10-3 K-1 and c = -1.55  105 K2. Calculate the value of the constant pressure molar heat capacity at 25.0 °C.

The mean bond enthalpy of a P-Cl bond is 331 kJ mol-1 and of a Cl-Cl bond is 242 kJ mol- at 298 K. If the mean standard enthalpy of atomization of white phosphorus is 315 kJ mol-1, estimate the standard enthalpy of formation of gaseous phosphorus trichloride, PCl3, at this temperature.

The constant pressure molar heat capacity of methane, CH4, is 35.31 J K-1 mol-1 at temperatures close to 298 K. Calculate the enthalpy change when 2.00 mol of methane is heated from a temperature of 278 K to 318 K.

The heat capacity of a bomb calorimeter and its contents was measured to be 6.14 kJ K-1. Calculate the change in temperature when a current of 245 mA from a 12.0 V source was allowed to flow through the electrical heater for a period of 254 s.

The standard enthalpy of formation of gaseous diborane, B2H6, is +31 kJ mol-1 at 298 K. Use the following data for the molar heat capacities at constant pressure to determine the standard enthalpy of reaction at 450 K. Cp,mo / kJ mol-1 B(s) 12.0 H2(g) 28.8 B2H6(g) 56.4

When 7.82 g of benzaldehyde, C6H5CHO, was burned in a bomb calorimeter at 298.15 K, the heat released was 259.2 kJ. Calculate the enthalpy of combustion of benzaldehyde at this temperature.

Calculate the expansion work done on the system when exactly 1 mol of solid ammonium chloride, NH4Cl, decomposes completely to yield gaseous ammonia, NH3 and hydrogen chloride, HCl at a temperature of 1250 K. Treat the expansion as irreversible and the gases formed as perfect.

Use the following data to determine the standard enthalpy of reaction at 298 K for the addition of hydrogen chloride, HCl, to ethene, C2H4 C2H4(g) + HCl(g) ? C2H5Cl(g) \Delta\ (298)/ +52.2 -92.3 -109.8

The constant pressure molar heat capacity of argon is 20.79 J K-1 mol-1 at 298 K. Predict the value of the constant volume molar heat capacity of argon at this temperature.

The constant pressure molar heat capacity of zinc is 25.40 J K-1 mol-1 at 298 K. Calculate the constant pressure specific heat capacity of zinc at this temperature.

Calculate the heat transferred to the system when 1.00 mol of a perfect gas expands reversibly at a constant temperature of 25°C so that its volume doubles.

The molar heat capacity of solid aluminium is 24.4 J K-1 mol-1 at 25°C. Calculate the change in internal energy when 1.00 mol of solid aluminium is heated from a temperature of 20°C to 30°C.

The enthalpy of vaporization of tetrachloromethane, CCl4, is 30.5 kJ mol-1 at its normal boiling temperature of 350 K. Estimate the enthalpy of vaporization at 298 K, given that the molar constant pressure heat capacities of liquid and gaseous tetrachloromethane are 83.5 and 135 J K-1 mol-1.

The Propertiesof Gases

The Second Law of Thermodynamics

Physical Transformations

Chemical Change

Chemical Kinetics

Quantum Theory

Atomic Structure

The Chemical Bond

Molecular Interactions

Molecular Spectroscopy

Statistical Thermodynamics

Filters

The mean bond enthalpy of a P-Cl bond is 331 kJ mol^-1 and of a Cl-Cl bond is 242 kJ mol^-at 298 K. If the mean standard enthalpy of atomization of white phosphorus is 315 kJ mol^-1, estimate the standard enthalpy of formation of gaseous phosphorus trichloride, PCl₃, at this temperature.

The constant pressure molar heat capacity of methane, CH₄, is 35.31 J K^-1 mol^-1 at temperatures close to 298 K. Calculate the enthalpy change when 2.00 mol of methane is heated from a temperature of 278 K to 318 K.

The heat capacity of a bomb calorimeter and its contents was measured to be 6.14 kJ K^-1. Calculate the change in temperature when a current of 245 mA from a 12.0 V source was allowed to flow through the electrical heater for a period of 254 s.

The standard enthalpy of formation of gaseous diborane, B₂H₆, is +31 kJ mol^-1 at 298 K. Use the following data for the molar heat capacities at constant pressure to determine the standard enthalpy of reaction at 450 K. C_p,_m^o / kJ mol^-1 B(s) 12.0 H₂(g) 28.8 B₂H₆(g) 56.4

When 7.82 g of benzaldehyde, C₆H₅CHO, was burned in a bomb calorimeter at 298.15 K, the heat released was 259.2 kJ. Calculate the enthalpy of combustion of benzaldehyde at this temperature.

Calculate the expansion work done on the system when exactly 1 mol of solid ammonium chloride, NH₄Cl, decomposes completely to yield gaseous ammonia, NH₃ and hydrogen chloride, HCl at a temperature of 1250 K. Treat the expansion as irreversible and the gases formed as perfect.

Use the following data to determine the standard enthalpy of reaction at 298 K for the addition of hydrogen chloride, HCl, to ethene, C₂H₄ C₂H₄(g) + HCl(g) ? C₂H₅Cl(g) \Delta\ (298)/ +52.2 -92.3 -109.8

The constant pressure molar heat capacity of argon is 20.79 J K^-1 mol^-1 at 298 K. Predict the value of the constant volume molar heat capacity of argon at this temperature.

The constant pressure molar heat capacity of zinc is 25.40 J K^-1 mol^-1 at 298 K. Calculate the constant pressure specific heat capacity of zinc at this temperature.

The molar heat capacity of solid aluminium is 24.4 J K^-1 mol^-1 at 25°C. Calculate the change in internal energy when 1.00 mol of solid aluminium is heated from a temperature of 20°C to 30°C.

The enthalpy of vaporization of tetrachloromethane, CCl₄, is 30.5 kJ mol^-1 at its normal boiling temperature of 350 K. Estimate the enthalpy of vaporization at 298 K, given that the molar constant pressure heat capacities of liquid and gaseous tetrachloromethane are 83.5 and 135 J K^-1 mol^-1.