Molecular Physics | Thermodynamics Answers

Old trains were powered by steam engines. What was most likely needed to produce the steam to power a train?

a. Ice and a furnace to create water.
b. Water and a way to heat the water.
c. Water and very cold chemical to freeze water.
d. Water vapor and a way to cool it to create water.

A steady flow of steam enters a condenser with a specific enthalpy of 2300 kJ/kg and a velocity of 350 m/s. The condensate leaves the condenser with a specific enthalpy of 160 kJ/kg and a velocity of 70 m/s. Calculate the heat transfer to the cooling fluid per kilogram of steam condensed.

An inventor claims to have constructed an engine that has an efficiency of when operated 75% when operated between the boiling and freezing points of water. Is this possible ? Illustratively explain.

How much energy is released when 130.00 g of steam at 103.0 °C if cooled to ice at
–12.5 °C? Please show work

An Erlenmeyer flask of surface area 0.8 m2 and wall thickness 2 cm is filled with water at 0 oC. The Erlenmeyer flask is then immersed in a glass beaker filled with water at a temperature of 30 oC. What is the heat current? How long does it take for 12 J of heat energy to be transferred to the water in the Erlenmeyer flask?

3. A tank of volume 0.3 m3
contains 2 moles of helium gas at 20℃. Assuming the
helium behaves like an ideal gas,
3.1. Find the total internal energy of the system.
3.2. What is the average kinetic energy per molecule?

When a person plucks a guitar string the number of the half wavelengths that fit into the length of the string determines the ______ of the sound produced.

If a kettle is not 100% efficient where does the missing energy go? And is there a way of improving the efficiency of a kettle?

3. n moles of an ideal gas undergo an isobaric process 1->2 and then the isochoric process 2->3 shown in Fig. 1 in such was that the gas performs work A. The ratio of P2 and P3 is known: P2/P3=k. The temperature T1 in the state 1 equals to the temperature T3 In state 3. Calculate temperature T3.

4. A monoatomic gas takes up a volume of V=4m3 and is at a pressure of 8x105 Pa. The gas undergoes an isothermal expansion reaching the final pressure of 1 atm. Calculate a) the work done to the gas in such a process b) the amount of heat absorbed by the gas c) change in the internal energy of the gas.

Using Maxwell’s relations derive first and second energy equations. Using first energy equation, show that the internal energy of an ideal gas is independent of its volume.