Question

please answer all questions

A)-5184 B) 1000 7 A vacuum pump reduces the absolute pressure of a container to 1.5x10 Pa. The volume of the e D) 1.5 x10 ontainer is 2.5 m and the temperature of the gas is 300K. How many molecules of gas are left in the contai B) 1.5 x 106 A) 9.06 x104 C) 1.38 x1023 hree moles of an ideal gas are compressed from 55 x 102 to 2.5 x 10 m. During the compression,6.1 x 10 of wo one on the gas, and heat is removed to keep the temperature of the gas constant at all times. What type is this thermal process? A ) isobaric A) -273 K A) 130 J B) isochoric B)0K B) 0 J C) isothermal C) 273 K C) 3400 J D) adiabatic D) 43 K D) 6.1 x 10 9Determine the change in internal energy of the gas in question 8 10 Determine the heat removed from the gas in question 8.

Answer 1

7) using the universal gas equation we have

PV = nRT

(1.5*10^-6 /1.01325*10^5) * 2500 = n*0.0821*300

n = 1.5*10^-9

number of molecules = Na*n

where Na = Avogadro's number

No. of molecules = 6.023*10^23*1.5*10^-9 = 9.06*10^14

so option A) is the correct answer

8) since the temperature of the gas is constant

it is isothermal process

option C) is the correct answer

9) change in internal energy = nCv*dT

where dT = change in temperature

which is 0 in case of isothermal process

so change in internal energy is zero

option B) is the correct answer

10) according to first law of thermodynamics

Q = del U + W

Q = 0 + W

Q = -6.1*10^3 J

so heat removed from the system is 6.1*10^3 J

so option D) is the correct answer