Conceptual
Calculations
100

Describe what the ideal gas law means (no equations)

The ideal gas law describes the relationship between the "state variables" temperature, pressure, and volume. Pressure and volume are directly related to temperature and number of moles (molecules)while pressure is inversely related to volume. They are related by a constant of proportionality (either R or k).

100

Calculate the mass of a mole of dry air, which is a mixture of N2 (78% by volume), O2 (21%), and argon (1%). (Hint: use periodic table)

29 g

200

Compare and contrast heat and work

The both are forms of energy transfer. Heat transfer occurs due to a temperature difference. Work is any other type of energy transfer in a system.

200

Problem 1.45 parts (a)+(b)

(a) w=(y^2)(z) and w=(x2)/(z)

(b) (dw/dx)y = y

      (dw/dx)z = 2x/z


300

Describe what the first law of thermodynamics means (no equations)

The total energy that enters a system as heat or work is the amount the system's energy changes due to conservation of energy
300

By applying a pressure of 200 atm, you can compress water to 99% of its usual volume. Sketch this process (not necessarily to scale) on a PV diagram, and estimate the work required to compress a liter of water by this amount. (hint: a joule is = (atm)(L))

100 J

400

A battery is connected in series to a resistor, which is immersed in water (to prepare a nice hot cup of tea). Would you classify the flow of energy from the battery to the resistor as heat or work? What about the flow of energy from the resistor to the water?

Energy from the battery to the resistor is work

Energy from the resistor to the water is heat

400

In a Diesel engine, atmospheric air is quickly compressed to about 1/20 of its original volume. Estimate the temperature of the air after compression, and explain why a Diesel engine does not require spark plugs. (Hint: this is an adiabatic process)

~1000 K

500

Describe what the enthalpy of an material means (no equations)

Enthalpy is the total energy of a system plus the work necessary to make room for that system

500

Problem 1.51: Use the data at the back of this book to determine the change in enthalpy for the combustion of a mole of glucose, 

C6H12O6 + 6O2 ----> 6CO2 + 6H2O

dHglucose = +1273 kJ (negative enthalpy of formation of glucose)

dHco2+H20 = 6(-393.5 kJ) + 6(-285.8 kJ) = -4076 kJ


dHtotal = -2803 kJ


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