Chemistry - Ideal Gas Law

You have a weather balloon that is filled with Helium (He) and has a diameter of 3 ft. Find the mass in grams of the He in the balloon at 21 degrees Celsius and normal pressure. And the density of He with these conditions is .166 g/L.

My Work:
V=4/3 * pi * r^3 V = 14.1 ft^3 * (28.3 L/1 ft^3) = 399 L

T = (21 + 273)K = 294 K

R = .0821 L*atm/(K*mol) ---> Not sure if this is correct value to use.

P = 1 atm ---> Not sure if this is correct value to use.

M = 4.00 g/mol

Using ideal gas law

m = (PMV)/(RT)

m=(1 atm * 4.00 g/mol * 399 L)/(.0821 L*atm/(K*mol) * 294 K)

m = 66.1 g Helium

How does this look?

  1. 👍 0
  2. 👎 0
  3. 👁 221
  1. It's close to what I have but with a lot more work. I think you have converted to STP but I think the problem is asking for mass He at the temperature of 21 C and not 0 C.
    Here is what I did. Check me out on this.
    First, I didn't know the conversion for cu ft so
    3 ft x (12 inches/ft)x (2.54 cm/in)/2 = radius = 45.72 cm
    V = (4/3)*pi*(45.72)3 = 400,319 cc = 400.32 L
    The problem states that the density under these conditions; i.e., normal pressure and 21 C) is 0.166 g/L so
    400.32 x 0.166 = 66.453 which I rounded to 66.4 L.

    1. 👍 0
    2. 👎 0
    posted by DrBob222
  2. oops. That's 66.4 grams, not L.

    1. 👍 0
    2. 👎 0
    posted by DrBob222
  3. Oh so technically the ideal gas law wasn't needed. That makes more sense as to why the density was put in the problem.

    1. 👍 0
    2. 👎 0

Respond to this Question

First Name

Your Response

Similar Questions

  1. physics

    a spherical balloon of diameter 2m is filled with helium.Assume STP .how much is contained in the balloon helium

    asked by Anonymous on May 1, 2015
  2. Physics

    A 1.8-g balloon is filled with helium gas. When a mass of 4.8 g is attached to the balloon, the combined mass hangs in static equilibrium in midair. Assuming that the balloon is spherical, what is its diameter? (The density of

    asked by mymi on November 7, 2011
  3. Physics

    A balloon with a mass of 90 kg is filled with helium (density = 0.179 kg/m3). The balloon is spherical and has a diameter of 11.0 m. What is the maximum mass that can be attached to the bottom of this this helium balloon, for it

    asked by Alphonse on January 17, 2013
  4. Physics

    A spherical helium filled balloon is attached to a string that is fixed to the ground. the balloon has a volume of .30/4m^3 and helium has a density of .20 kg/m^3. What is the weight of the balloon and helium if the tension on the

    asked by George on October 11, 2013
  5. Physics

    A spherical helium filled balloon is attached to a string that is fixed to the ground. the balloon has a volume of .30/4m^3 and helium has a density of .20 kg/m^3. What is the weight of the balloon and helium if the tension on the

    asked by George on October 11, 2013
  6. chemistry

    A weather balloon is filled with 0.295 m3 of helium on the ground at 18 °C and 756 torr. What will the volume of the balloon be at an altitude of 10 km where the temperature is 48 °C and the pressure is 0.14 atm?

    asked by jun on November 5, 2014
  7. chemistry

    A helium-filled balloon of the type used in long-distance flying contains 420,000 ft3 (1.2 times 107 L) of helium. Suppose you fill the balloon with helium on the ground, where the pressure is 737 mm Hg and the temperature is 16.0

    asked by Helpme on March 30, 2007
  8. Physics

    A spherical helium filled balloon is attached to a string that is fixed to the ground. the balloon has a volume of .30/4m^3 and helium has a density of .20 kg/m^3. What is the weight of the balloon and helium if the tension on the

    asked by George on October 11, 2013
  9. chemistry

    a weather balloon with a 2 meter diameter at ambiient tempatures holds 525 grams of helium. what type of electroniic probe could be used to determine the pressure inside the balloon

    asked by eric on January 18, 2011
  10. physic

    an empty rubber balloon has 0.0120 kg it filled of helium. the density of helium is 0.179 kg/m^3 of and the radius of the balloon is 0.500 what is the buoyant force over the balloon

    asked by Sue on December 5, 2015

More Similar Questions