# physics- pressure/gas

posted by .

Suppose 2500 J of heat are added to 4.1 mol of argon gas at a constant pressure of 120 kPa. (Assume that the argon can be treated as an ideal monatomic gas.) Find the change in internal energy.
I started using U = N (3/2 kB T). But I have too many unknowns. The only other equation that our teacher gave us is Won + Qon = deltaU (Work on system + Heat on system = Change in internal energy). Please help!

Qon = deltaU - Won =

deltaU + Wsystem,

where Wsystem is the work performed by the system (in this case the argon gas). Because the pressure is constant, the work performed is:

P deltaV = Delta (PV) = (using ideal gas law) Delta (N kB T)

This means that:

Qon = deltaU + Wsystem =

5/2 N kB delta T =

(5/2)(2/3)(3/2)N kB delta T =

(5/2)(2/3) delta U = 5/3 delta U

And it follows that:

delta U = 3/5 Qon = 1500 J

## Similar Questions

1. ### Physics HELP!!!!!!!!

Suppose a monatomic ideal gas is contained within a vertical cylinder that is fitted with a movable piston. The piston is frictionless and has a negligible mass. The area of the piston is 3.06 10-2 m2, and the pressure outside the …
2. ### physics

A container of volume 0.39 m3 contains 8.7 mol of argon gas at 32◦C. Assuming argon behaves as an ideal gas, find the total internal energy of this gas. Answer in units of J.Given: R = 8.31451 J/mol • K.
3. ### Physics

A cylinder with a moveable piston holds 2.60 mol of argon at a constant temperature of 295 K. As the gas is compressed isothermally, its pressure increases from 101 kPa to 149 kPa. (a) Find the final volume of the gas. Answer in m3 …
4. ### physics

A cylinder with a movable piston holds 2.75 mol of argon gas at a constant temperature of 295 K. As the gas is compressed isothermally, its pressure increases from 101 kPa to 121 kPa. Find (a) the final volume of the gas, (b) the work …
5. ### Physics

A monatomic ideal gas expands from 1.00m^3 to 2.50m^3 st a constant pressure of 2.00x10^5 Pa. Find the change in the internal energy of the gas.
6. ### Physics

Suppose 2100 J of heat are added to 3.3 mol of argon gas at a constant pressure of 120 kPa. (Assume that the argon can be treated as an ideal monatomic gas.) A) Find the change in internal energy. B) Find the change in temperature …
7. ### Physics I

A container of volume 0.71 m3 contains 1 mol of argon gas at 27◦C. Assuming argon behaves as an ideal gas, find the total internal energy of this gas. The value of gas constant is 8.31451 J/mol · K
8. ### Physics

A tank with a constant volume of 3.44 m3 contains 14 moles of a monatomic ideal gas. The gas is initially at a temperature of 300 K. An electric heater is used to transfer 52600 J of energy into the gas. It may help you to recall that …
9. ### Physics

A cylinder with a movable piston contains 14 moles of a monatomic ideal gas at a pressure of 2.26 × 105 Pa. The gas is initially at a temperature of 300 K. An electric heater adds 52600 J of energy into the gas while the piston moves …
10. ### physics

Argon is a monatomic gas whose atomic mass is 39.9 u. The temperature of eight grams of argon is raised by 95 K under conditions of constant pressure. Assuming that argon behaves as an ideal gas, how much heat is required?

More Similar Questions