Solve the following problems. You may work in groups if you wish, but every student must hand in his/her own copy. You must show all of your work and calculations, not just the answer!
Problems
1. The end of an insulated metal rod is maintained at 100°C and the other is maintained at 0°C by an ice water mixture. The rod is 60.0 cm long and has a cross section of 1.25 cm2. The heat conducted by the rod melts 8.50 g of ice in 10.0 mins. Find the thermal conductivity of the metal.
2. A pot with a steel bottom 8.50 mm thick rests on a hot stove. The area of the bottom of the pot is 0.150 m2. The area inside the pot is at 100.0°C and 0.390 kg of water is evaporated every 3.00 mins. Find the temperature of the lower surface of the pot, which is in contact with the stove.
3. The temperature of a tungsten filament in an incandescent light bulb is 2180°C. The emissivity of tungsten (ε) is 0.35. What is the surface area of the filament in a 100W light bulb if all the electrical energy consumed by the bulb is radiated by the filament?
4. If the barometric pressure is 97.4 kPa how much is it mm Hg? In atm?
5. If a manometer indicates an excess pressure equal to a water column of 15.2 cm, how much is the excess pressure in Pa?
6. Helium gas with a volume of 2.60 L, under a pressure of 1.3 atm and at a temperature of 41.0°C is heated until both the pressure and volume are doubled.
a) What is the final temperature?
b) What is the mass of helium in the system? The molar mass of He is MHe = 4.00 g/mol.
7. Three moles of an ideal gas are in a rigid cubical box measuring 0.2 x 0.2 x 0.2 m. What is the force that the gas exerts on each of the 6 sides of the box at a temperature of 20°C? What is the force if the temperature of the gas increases to 100°C.
8. Consider a CH4 (methane) storage tank with a volume of 49 L. When empty, the tank has a mass of 55.85 kg, and when filled, its mass is 62.05 kg. Calculate the pressure of CH4 in the tank at an ambient temperature of 21°C using both the ideal gas law and the van der Waals equation. What is the percentage error obtained by using the ideal gas law compared to the more realistic van der Waals equation? The molar mass of CH4 is 16 g/mol.
9. What is the average translational kinetic energy of a molecule in air at a temperature of 22°C?