22. A 44.97−g sample of water at 72.2°C is added to a sample of water at 25.7°C in a constant-pressure calorimeter. If the final temperature of the combined water is 38.4°C and the heat capacity of the calorimeter is 26.3 J/°C, calculate the mass of the water originally in the calorimeter.

The temperature of the cooling water as it leaves the hot engine of an automobile is 240 F. After it passes through the radiator it has a temperature of 175 F. Calculate the amount of heat transferred from the engine to the surroundings by one gallon of water with a specific heat of 4.184 J/g oC.

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.

When solid iron burns in oxygen gas (at constant pressure) to produce Fe2O3(s), 1651 kJ of heat is released for every 4 mol of iron burned. How much heat is released when 10.3 g Fe2O3(s) is produced (at constant pressure)? What additional information would you need to calculate the heat released to produce this much Fe2O3(s) if you burned iron in ozone gas, O3(g), instead of O2(g)?

Under what circumstances is the heat of a process equal to the enthalpy change for the process?

Salicylic acid, C7H6O3, is one of the starting materials in the manufacture of aspirin. When 1.00 g of salicylic acid burns in a bomb calorimeter, the temperature of the bomb and water goes from 23.11C to 28.91C. The calorimeter and water absorb 21.9 kJ of heat. How much heat is given off when one mole of salicylic acid burns?

The enthalpy change for the following reaction is 393.5 kJ. C(s,graphite)+O2(g)CO2(g) (a) Is energy released from or absorbed by the system in this reaction? (b) What quantities of reactants and products are assumed? (c) Predict the enthalpy change observed when 3.00 g carbon burns in an excess of oxygen.

A 10.00-g sample of acetic acid, HC2H3O2, was burned in a bomb calorimeter in an excess of oxygen. HC2H3O2(l)+2O2(g)2CO2(g)+2H2O(l) The temperature of the calorimeter rose from 25.00C to 35.84C. If the heat capacity of the calorimeter and its contents is 13.43 kJ/C, what is the enthalpy change for the reaction?

9.97 Suppose that the working fluid inside an industrial refrigerator absorbs 680 J of energy for every gram of material that vaporizes in the evaporator. The refrigerator unit uses this energy flow as part of a cyclic system to keep foods cold. A new pallet of fruit with a mass of 500 kg is placed in the refrigerator. Assume that the specific heat of the fruit is the same as that of pure water because the fruit is mostly water. Describe how you would determine the mass of the working fluid that would have to be evaporated to lower the temperature of the fruit by 15C. List any information you would have to measure or look up.

Compounds with carboncarbon double bonds, such as ethylene, C2H4, add hydrogen in a reaction called hydrogenation. C2H4(g)+H2(g)C2H6(g) Calculate the enthalpy change for this reaction, using the following combustion data: C2H4(g)+3O2(g)2CO2(g)+2H2O(l);H=1411kJC2H6(g)+72O2(g)2CO2(g)+3H2O(l);H=1560kJH2(g)+12O2(g)H2O(l);H=286kJ