Consider the following reaction at 235°C and 1.00 atm: CH3 CI(g) + H2 (9) → CH4 (g) + HC1(g) For this reaction, the enthalpy change at 235°C is -83.2 kJ/mol. You may need to use the following data: Substance and State AĦƐ (kJ/mol) C,(J°Cmol¯1) CH3 Cl(g) 48.5 H2 (g) 28.9 CH4 (g) -75 41.3 HCl(g) -92 29.1 a Assuming that the C, values are independent of temperature, calculate AH° for this reaction at 25°C. ΔΗ' kJ/mol

The head of a strike anywhere match contains tetraphosphorus trisulfide, P4S3. In an experiment, a student burned this compound in an excess of oxygen and found that it evolved 3651 kJ of heat per mole of P4S3 at a constant pressure of 1 atm. She wrote the following thermochemical equation: P4S3(s)+8O2(g)P4O10(s)+3SO2(g);H=3651kJ Calculate the standard enthalpy of formation of P4S3, using this students result and the following standard enthalpies of formation: P4O10(s), 3009.9 kJ/mol; SO2(g), 296.8 kJ/mol. How does this value compare with the value given in Appendix C?

The enthalpy of combustion of diamond is -395.4 kJ/mol. C s, dia O2 g CO2 g Determine the fH of C s, dia.

A sample of benzene, C6H6, weighing 3.51 g was burned in an excess of oxygen in a bomb calorimeter. The temperature of the calorimeter rose from 25.00C to 37.18C. If the heat capacity of the calorimeter and contents was 12.05 kJ/C, what is the value of q for burning 1.00 mol of benzene at constant volume and 25.00C? The reaction is C6H6(l)+152O2(g)6CO2(g)+3H2O(l) Is q equal to U or H?

Nitrogen gas (2.75 L) is confined in a cylinder under constant atmospheric pressure (1.01 105 pascals). The volume of gas decreases to 2.10 L when 485 J of energy is transferred as heat to the surroundings. What is the change in internal energy of the gas?

A sample of ethanol, C2H5OH, weighing 2.84 g was burned in an excess of oxygen in a bomb calorimeter. The temperature of the calorimeter rose from 25.00C to 33.73C. If the heat capacity of the calorimeter and contents was 9.63 kJ/C, what is the value of q for burning 1.00 mol of ethanol at constant volume and 25.00C? The reaction is C2H5OH(l)+3O2(g)2CO2(g)+3H2O(l) Is q equal to U or H?

White phosphorus, P4, ignites in air to produce P4O10. When 3.56 g P4 is burned, 85.8 kJ of thermal energy is evolved at constant pressure. Calculate the combustion enthalpy of P4.

One of the components of jet engine fuel is n-dodecane, C12H26(), which has a standard enthalpy of combustion of 8080.1 kJ/mol. (a) Write the thermochemical equation for the combustion of n-dodecane. (b) Use the standard enthalpies of formation in Appendix G to calculate the standard enthalpy of formation of n-dodecane.

A 50-mL solution of a dilute AgNO3 solution is added to 100 mL of a base solution in a coffee-cup calorimeter. As Ag2O(s) precipitates, the temperature of the solution increases from 23.78 C to 25.19 C. Assuming that the mixture has the same specific heat as water and a mass of 150 g, calculate the heat q. Is the precipitation reaction exothermic or endothermic?

In a constant-volume calorimeter, 35.0g of H2cools from 75.3C to25.0C. Calculate w, q, U, and H for the process.