Chemistry

What is the molecular weight of a gas if a 15.0g sample has a pressure of 836 mm Hg at 25.0 degrees C in a 2.00 L flask?

a)167
b)1.35
c)176
d)11.1
e)none of the above


Please explain... I need to understand how to do this. Thanks.

  1. 👍 0
  2. 👎 0
  3. 👁 135
asked by Coug
  1. Use PV = nRT to solve for n.
    Then n = grams/molar mass.

    1. 👍 0
    2. 👎 0
    posted by DrBob222
  2. I'm still confused... I know that:
    P=1.1 atm
    V=2.00 L
    n=?
    R= I think .0821
    and
    T= ?

    I have no idea how to change 15.0g to moles, since I do not know what the element is to look at the atomic mass--I know that one mole is avagadro's number, but I'm still really not sure what to do here.

    Please help...

    1. 👍 0
    2. 👎 0
  3. T- 25+273 = 298k

    n=PV/RT

    n= 1.1 atm*2.00 l/ (0.0821 (L*atm/ mol*k) *298k)
    n=0.0899mol
    MW= 5.0g/0.0899mol

    =167amu

    1. 👍 0
    2. 👎 0
    posted by ricky

Respond to this Question

First Name

Your Response

Similar Questions

  1. Chemistry

    I don't understand how to answer this questions. I thought molecular weight was adding up the atomic weight of each element in a molecule...? If a 0.614g sample of a gas maintains a pressure of 238 mmHg when contained in a 1.0L

    asked by Holly Y. on November 8, 2009
  2. Chemistry

    A student performed an experiment to determine the molecular weight of a gaseous compound. Using the ideal gas law PV = nRT, and knowing the pressure, temperature, and volume of the vapor, the student calculated the number of

    asked by Ericka on November 15, 2015
  3. Chem 101

    A 5.00 liter sample of gas measured at 27 degrees Celcius and 1.25 atm of pressure has a mass of 10.13 grams. What is the molecular weight of the gas in u?

    asked by Joni on November 30, 2011
  4. Chem

    A sample of gas of mass 2.929 g occupies a volume of 426 mL at 0degree Cel and 1.00 atm pressure. What is the molecular weight of the gas? Thanks!

    asked by Peter on March 9, 2010
  5. Chemistry

    The molecular weight of an unknown gas is found by measuring the time required for a known volume of the gas to effuse through a small hole, under constant pressure. The apparatus is calibrated by measuring the time needed for the

    asked by Gi on July 19, 2018
  6. Chemistry

    What is the molecular weight of a gas if a 21.0g sample has a pressure of 836mm Hg at 25.0 degrees C in a 2.00L flash?

    asked by Shirley on December 7, 2010
  7. fluid mechanics

    a gas well containd hydrocarbon gases with an average molecular weight of 24, which can be assumed to be an ideal gas with a specific heat ratio 1.3. The pressure and temperature at the top of the well are 250psig and 708F,

    asked by adigun. on November 18, 2014
  8. chemistry

    3.58 gram sample of an unknown gas is found to occupy a volume of 2.37 L at a pressure of 808 mm Hg and a temperature of 60 oC. What is the molecular weight?

    asked by Anonymous on April 3, 2015
  9. Miami trace

    Chemistry. AN UNKNOwn gas has a pressure of 2.0, a volume of 15.0 L and a temperature of 348 Kelvin. The sample weighs 4.20 grams. What is its molecular weight. I am trying to find formula

    asked by corey on November 30, 2015
  10. Science

    10. You analyze the gas in 100 kg of gas in a tank at atmospheric pressure, and find the Following : CO2;19.3%, N2;72.1%, O2;6.5%, H2O;2.1% What is the average molecular weight of the gas?

    asked by Man Singh Chouhan on March 26, 2015

More Similar Questions