Problems
2.1 Heat is transferred to a system at 1 atm. Will the internal energy increase more if the system
is at constant volume or at constant pressure?
2.2 For the isothermal, reversible compression of an ideal gas, what can be said about the heat?
2.3 Burning gasoline inside a closed, adiabatic system at constant volume will cause what change
to the internal energy?
2.4 What can be stated about the internal energy of an isolated system?
2.5 Why do drug candidates have different ITC profiles?
2.6 What type of heat dependence would a favorable drug candidate have?
2.7 If 0.818 mol of an ideal gas at 25°C is in a 2-L container that is expanded to a final volume
of 8 L at a constant pressure of 1 atm, what are the heat, work, and change in internal energy?
2.8 What is the work involved in an isothermal, reversible expansion of 0.5 mol of an ideal gas
at 30°C from 10 to 20 L?
2.9 A 5-g block of dry ice is placed into a 30-mL container and the container is sealed. (a) What
is the pressure in the container after the carbon dioxide has sublimated (vaporized directly to
gas; Chapter 4)? (b) Assuming that the pressure is immediately released after the pressure
fully develops, how much work is done on the surroundings by the expansion of the gas?
Neglect any contribution from the cap.
2.10 A sealed 1-L glass container at 1 atm and 25°C is heated and breaks when the internal
pressure reaches 2 atm. When it breaks what is the temperature inside and what is the
internal energy? Assume that the specific heat of air has the value of CV=25 J/(Kmol).
2.11 What is the enthalpy change of a system if 1.0 J of heat is transferred into it at constant
pressure?
2.12 If an ideal gas expands isothermally, what can be said about the internal energy?
2.13 One mole of an ideal gas is in a piston and the volume changes from 2 to 4 L at 25°C. What
are the work, heat, and change in the internal energy?
2.14 Calculate the heat required to raise the temperature of 1.5 mol of an ideal gas from 15 to
50°C when the volume is fixed at 1 L. What is the change in internal energy using a specific
heat value of CV=25 J/(Kmol)?
2.15 If 2 mol of an ideal gas is allowed to expand isothermally and reversibly from 10 to 30 L
at a constant temperature of 20°C, what are the work, heat, and change in internal energy?
2.16 What is the enthalpy of combustion for sucrose?
2.17 How reliable is the melting of the glaciers as an indicator of the temperature if some glaciers
are increasing in mass?
2.18 If the amount of carbon dioxide generated by several different biological processes is so large,
why should we be concerned about the increase generated by industry and transportation
during the past 50 years?
2.19 If the distance between the Earth and Sun decreased by 5% due to an extraterrestrial disaster,
how much would the temperature of the Earth change?
2.20 How much would the solar radiation need to increase in order to increase the temperature
of the Earth by 10% (neglecting the atmosphere)?