# Physics

A sample of helium behaves as an ideal gas as it is heated at constant pressure from 273 K to 373 K. If 15.0 J of work is done by the gas during this process, what is the mass of helium present?

I am not sure what equations to use for this problem....

1. 👍
2. 👎
3. 👁
1. PV=nRT
p dV + V dp = n R dT
p is constant here so
p dV = n R dT
work = integral p dV = nR dT
p(V2-V1) = n R (T2-T1)

so 15 = n R (T2-T1)

1. 👍
2. 👎
2. doesnt that give me an answer in moles? ...is there a way to convert moles to mg?

1. 👍
2. 👎
3. so i got the answer to be .01804 moles

and i know one mole of helium is 4.03 g

do i just multiply the two together? and then divide by 10000 to convert g to mg?

1. 👍
2. 👎
4. never mind. I made a silly error.

i got .01804 moles...multiplied that times 4.03grams and then multiplied that times 1000 and got 72.7mg.

got it! thanks so much!

1. 👍
2. 👎
5. what are we solving for in this equation?? 15 = n R (T2-T1)
we know n, we know R, we know t1 and t2...so what do we solve for?

1. 👍
2. 👎

## Similar Questions

1. ### Chemistry

a sample of helium gas is in a closed system with a movable piston. the volume of the gas sample is changed when both the temperature and the pressure of the sample are increased. the table below shows the initial temperature,

2. ### Chemistry

A 334-mL cylinder for use in chemistry lectures contains 5.225 g of helium at 23 C. How many grams of helium must be releasedto reduce the pressure to 75 atm assuming ideal gas behavior?

3. ### chemistry

If I contain 3 moles of gas in a container with a volume of 60 liters and at temperature of 400 K, what is the pressure inside the container? Ideal Gas Law: PV=nRT I know I'm given the volume, temperature, and numbers of moles of

4. ### Physics

A sealed container of volume 0.10 m3 holds a sample of 3.0 x 10^24 atoms of helium gas in equilibrium. The distribution of speeds of helium atoms shows a peak at 1100 ms-1. Caluculate the temperature and pressure of the helium

1. ### sciencee

1. What pressure would be needed to compress 25.1 mL of hydrogen at 1.01 atm to 25% of its original volume? 2. If the pressure on a 1.04-L sample of gas is doubled at constant temperature, what will be the new volume of the gas?

2. ### Chemistry

The volume of a sample of ideal gas at 25*C is 372ml. What will be the volume of the gas if it is heated at constant pressure to 50*C? What will be the volume of the gas if it is cooled to -272*C?

3. ### CHEM

A) a picture shows a container that is sealed at the top by a movable piston. Inside the container is a ideal gas at 1.00atm , 20.0 *C, and 1.00L. (The pic is of a 2L container which has a piston pushed downward to the 1L level.

4. ### science

As the pressure of a fixed mass of a gas is increased at constant temperature, the density of the gas increases? As the absolute temperature of a fixed mass of an ideal gas is increased at constant pressure, the volume occupied by

1. ### Chemical Engineering

High-pressure helium is available from gas producers in 0.045-m^3 cylinders at 400 bar and 298 K. Calculate the explosion equivalent of a tank of compressed helium in terms of kilograms of TNT. Assume helium is an ideal gas

2. ### physics

Helium gas occupies a volume of 0.04 m 3 at a pressure of 2 x 10 5 Pa (Nm -2 ) and temperature of 300 K. Calculate (i) the mass of the helium. (ii) the r.m.s. speed of its molecules. (iii) the r.m.s. speed at 432 K when the gas is

3. ### Chem hw!

1. What pressure would be needed to compress 25.1 mL of hydrogen at 1.01 atm to 25% of its original volume? 2. If the pressure on a 1.04-L sample of gas is doubled at constant temperature, what will be the new volume of the gas?

4. ### Chemical Engineering

High-pressure helium is available from gas producers in 0.045-m^3 cylinders at 400 bar and 298 K. Calculate the explosion equivalent of a tank of compressed helium in terms of kilograms of TNT. Assume helium is an ideal gas