One way to cool a gas is to let it expand. When a certain gas under a pressure of 5.00 106 Ha at 25.0C is allowed to expand to 3.00 times its original volume, its final pressure is 1.07 106 Pa. (a) What is the initial temperature of the gas in Kelvin? (b) What is the final temperature of the system? (See Section 10.4.)

Consider the latent heat of fusion and the latent heat of vaporization for H2O, 3.33 105 J/kg and 2.256 106 J/kg, respectively. How much heat is needed to a. melt 2.00 kg of ice and b. vaporize 2.00 kg of water? Assume the temperatures of the ice and steam are at the melting point and vaporization point, respectively. (a). UsingEq21.9, Q = mLF = (2.00 kg) (3.33l05 J/kg) = 6.66105 J (b).UsingEq21.10. Q = mLV = (2.00kg) (2.256106 J/kg) = 14.51106 J

Beryllium has roughly one-half the specific heat of water (H2O). Rank the quantities of energy input required to produce the following changes from the largest to the smallest. In your ranking, note any cases of equality, (a) raising the temperature of 1 kg of H2O from 20C to 26C (b) raising the temperature of 2 kg of H2O from 20C to 23C (c) raising the temperature of 2 kg of H2O from 1C to 4C (d) raising the temperature of 2 kg of beryllium from 1C to 2C (e) raising the temperature of 2 kg of H2O from -1C to 2C

(a) What is the rate of heat conduction through the 3.00-cm-thick fur of a large animal having a I .40-m surface area? Assume that the animal's skin temperature is 32.0 , that the air temperature is 5.00 , and that has the same thermal conductivity as air. (b) What food intake will the animal need in one day to replace this heat transfer?

An aluminum rod 0.500 m in length and with a cross sectional area of 2.50 cm2 is inserted into a thermally insulated vessel containing liquid helium at 4.20 K. The rod is initially at 3(H) K. (a) If one-halt of the rod is inserted into the helium, how many liters of helium boil off by the time the inserted half cools to 4.20 K? Assume the upper half does not yet cool, (b) If the circular surface of the upper end of the rod is maintained at 300 K. what is the approximate boil-off rate of liquid helium in liters per second after the lower half has reached 4.20 K? (Aluminum has thermal conductivity of 3 100 YV/m K at 4.20 K; ignore its temperature variation. The density of liquid helium is 125 kg/m3.)

During heavy exercise, the body pumps 2.00 L of blood per minute to the surface, where it is cooled by 2.00C. What is the rate of heat transfer from this forced convection alone, assuming blood has the same specific heat as water and its density is 1050kg/m3 ?

The specific heat of substance A is greater than that of substance B. Both A and B are at the same initial temperature when equal amounts of energy are added to them. Assuming no melting or vaporization occurs, which of the following can be concluded about the final temperature TA of substance A and the final temperature TB of substance B? (a) TA TB (b) TA TB (c) TA = TB (d) More information is needed.

Ice of mass 12.8 kg at 0°C is placed in an ice chest. The ice chest has 2.7 cm thick walls of thermal conductivity 0.07 W/m·K and a surface area of 1.29 m2. Express your answers with appropriate mks units. (a) How much heat must be absorbed by the ice during the melting process? (b) If the outer surface of the ice chest is at 39° C, how long will it take for the ice to melt?

(a) A 1.8 cm thick wooden floor covers a 4.0 m × 5.5 m room. The subfloor is at a temperature of 16.2 ˚C, while the air in the room is at 19.6 ˚C. What is the rate of heat conduction through the floor? The thermal conductivity for wood is 0.2 W / (m K) (b) Seals can cool themselves by using thermal windows, spots on their bodies with a much higher than average surface temperature. Suppose a seal has a thermal window of 0.030m2 at a temperature of 30˚C. If the seal's environment is frosted at -10˚C, what is the net rate of radiation energy loss? Assume an emissivity equal to 0.97. (please show steps, explanation and formulas)