Molecular Physics | Thermodynamics Answers

when water solidifies it increases its size....... does it behaves like this in vacuum as well???

A welded railway line, of length 15 km, is laid without expansion joints 

in a desert where the night and day temperatures differ by 50°C. The 

cross-sectional area of the rail is 3.6 × 10−3 m2. The rails are made of 

steel, which has Y = 2.0 × 1011 N/m2. (a) What is the difference in the 

night and day tension in the rail if it is kept at constant length? (b) If 

the rail is free to expand, by how much does its length change between 

night and day?

 A hypothetical substance has an isothermal compressibility κ = a/v

and volume expansion coefficient β = 2bT/v, where a and b are con￾stants and v is the molar volume. Show that the equation of state is

v b − + T aP = 2 constant

 Show that for small thermal expansions of a solid object the linear and 

volume coefficients of expansion are related by β ≈ 3α.

Ice at 0°C and 1 atm has a density of 916.23 kg/m3, while water under 

these conditions has a density of 999.84 kg/m3. How much work is 

done against the atmosphere when 10 kg of ice melts into water?

During a reversible adiabatic expansion of an ideal gas, the pressure 

and volume at any moment are related by PVγ = c where c and γ are 

constants. Show that the work done by the gas in expanding from a 

state (P1, V1) to a state (P2, V2) is

W PV P V = −

−

1 1 2 2

γ 1

An ideal gas undergoes the following reversible cycle: (i) an iso￾baric expansion from the state (P1,V1) to the state (P1,V2); (ii) an 
isochoric reduction in pressure to the state (P2,V2); (iii) an isobaric 
reduction in volume to the state (P2,V1); (iv) an isochoric increase 
in pressure back to the original state (P1,V1). (a) What work is done 
on the gas in this cycle? (b) If P1 = 3.0 atm, P2 = 1.0 atm, V1 = 1.0 L 
and V2 = 2.0 L, how much work is done on the gas in traversing the 

• cycle 100 times?

10 moles of an ideal gas are compressed isothermally and reversibly 

from a pressure of 1 atm to 10 atm at 300 K. (a) How much work is done 

on the gas? (b) How much work is done on the gas in the reverse process?

A platinum resistance thermometer measure temperature on the absorption that the change in electrical resistance of platinum is proportional to the change in temperature. The resistance of the platinum wire at zero degrees Celsius is 10.4ohms and 10.71ohms at 100°c

(1) what will be the resistance of the wire when the temperature is 45°c

a sample of gas held in 2.7m3 at a pressure of 226kPa. The temperature is kept constant while the pressure is increased to 484kPa. Calculate the the new volume of the gas.