Chapter 6

Identify the following systems as open, closed, or isolated: (a) coffec in a very high quality thermos bottle; (b) coolant in a refrigerator coil; (c) a bomb calorimeter in which benzene is bumed.

Identify the following systems as open, closed, or isolated: (a) gasoline burning in an automobile enginc; (b) mercury in a thermometer; (c) a living plant.

A gas sample is heated in a cylinder, using \(375 \mathrm{~kJ}\) of heat. At the same time a piston compresses the gas, using \(645 \mathrm{~kJ}\) of work. What is the change in internal energy of the gas during this process?

A gas sample in a piston axsembly expands, doing \(235 \mathrm{~kJ}\) of work on its surroundings at the same time that \(695 \mathrm{~kJ}\) of heat is added to the gas. (a) What is the change in internal encrgy of the gas churing this process? (b) Will the pressure of the gas be higher or lower when these changes are completed?

(a) Calculate the work for a system that absorbs \(150 \mathrm{~kJ}\) of heat in a process for which the increase in internal energy is \(120 \mathrm{~kJ}\). (b) Is work done on or by the system during this process?

(a) Calculate the work for a system that releases \(346 \mathrm{~kJ}\) of heat in a process for which the decrease in internal energy is \(125 \mathrm{~kJ}\). (b) Is work done on or by the system during this process?

A gas in a cylinder was placed in a heater and gained \(7000 \mathrm{~kJ}\) of heat. If the cylinder increased in volume from \(700 \mathrm{~mL}\) to \(1450 \mathrm{~mL}\) against an atmospheric pressure of 750 Torr during this process, what is the change in internal energy of the gas in the cylinder?

In a combustion cylinder, the total internal energy change produced from the burning of a fuel is \(-2573 \mathrm{~kJ}\). The cooling system that surrounds the cylinder absorbs \(947 \mathrm{~kJ}\) as heat. How much work can be done by the fuel in the cylinder during this process?

For a certain reaction at constant pressure, \(\Delta H=-15 \mathrm{~kJ}\) and \(22 \mathrm{~kJ}\) of expansion work is done on the system. What is \(\Delta U\) for this process?

For a certain reaction at constant pressure, \(\Delta U=-95 \mathrm{~kJ}\) and \(56 \mathrm{~kJ}\) of expansion work is done by the system. What is \(\Delta H\) for this process?