Molecular Physics | Thermodynamics Answers

The brick wall (of thermal conductivity 1.15 W/m · ◦ C) of a building has dimensions of 2.8 m by 9 m and is 24 cm thick. How much heat flows through the wall in a 5.5 h period when the average inside and outside temperatures are, respectively, 19◦C and 5◦C? Answer in units of MJ.

Three liquids are at temperatures of 6 ◦C, 20◦C, and 34◦C, respectively. Equal masses of the first two liquids are mixed, and the equilibrium temperature is 17◦C. Equal masses of the second and third are then mixed, and the equilibrium temperature is 25.3 ◦C. Find the equilibrium temperature when equal masses of the first and third are mixed. Answer in units of ◦C.

A piece of copper 700g is heated to100°c and then quickly transferred to a copper calorimeter of mass 20g containing 500g of liquid of unknown specific heat capacity of liquid calculate the specific heat capacity of copper 3900j/kg

Suppose the area of a window on a passenger jet is doubled in size

and all else is kept constant. Compared with the original window,

what will happen to the rate at which heat passes out through the

new window from the cabin?

The temperature on the inside face of a glass window is 20.0 .C

while the outside temperature is 0.00 .C. The window is 100 cm

by 100 cm by 10.0 mm and has a thermal conductivity of 0.85

W/m.K. How much energy passes outward through the glass in

Suppose that the heat flow out of your 20°C home in the winter is 7

kW. If the temperature outside is -15° C, how much power P would an

ideal heat pump require to keep your inside temperature at 20° C?

There is a 70 W heat leak from a room at temperature 22 °C into

an ideal refrigerator. How much electrical power is needed to

keep the refrigerator at -10 °C?

A large pot contains 5.00×10−3 m3 of water at 23.0 °C. How much thermal energy must be removed from the water to freeze it into ice at 0.00 °C (in MJ)? [Latent heat of fusion for water: 333.4 kJ kg−1 , specific heat of water: 4190 J kg−1 K−1 , density of water: 1000 kg m−3 .]

A certain fluid at 10 bar is contained in a cylinder behind a piston, the initial volume being 0.05^m3. Calculate the work done by the fluid when it expands reversibly according to linear law to a final volume of 0.2m^3 and a final pressure of 2 bars.