Nitrogen at 100 kPa and 25oC in a rigid vessel is heated until its pressure is 300 kPa. Calculate (a) the work done and (b) the heat transferred during this process, in kJ/kg. [use the room temperature specific heat for nitrogen] [for nitrogen Tcr=126.2 K, Pcr=3.39 MPa]

A. The work done during the process is W = 0

B. The value of heat transfer during the process Q = 442.83

Explanation:

Given Data

Initial pressure = 100 k pa

Initial temperature = 25 degree Celsius = 298 Kelvin

Final pressure = 300 k pa

Vessel is rigid so change in volume of the gas is zero. so that initial volume is equal to final volume.

⇒ = ------------- (1)

Since volume of the gas is constant so pressure of the gas is directly proportional to the temperature of the gas.

⇒ P ∝ T

⇒ =

⇒ Put all the values in the above formula we get the final temperature

⇒ = × 298

⇒ = 894 Kelvin

(A). Work done during the process is given by W = P × ()

From equation (1), = so work done W = P × 0 = 0

⇒ W = 0

Therefore the work done during the process is zero.

Heat transfer during the process is given by the formula Q = m ( - )

Where m = mass of the gas = 1 kg

= specific heat at constant volume of nitrogen = 0.743

Thus the heat transfer Q = 1 × 0.743 × ( 894- 298 )

⇒ Q = 442.83

Therefore the value of heat transfer during the process Q = 442.83

i had this question and the answer was 3.15 miles.

martina travels from school to her mom's office. from there, she walks to school. after school, she walks to the library and then to a friends house before finally ending back at home. find martina's total distance traveled.

a) 0 miles  

b) 0.4 miles  

c) 1 mile  

d) 3.15 miles