CHEM

A gaseous hydrocarbon (an organic compound consisting of C & H) weighing 0.232g occupies a volume of 102mL at 23 degrees Celcius and 749mmHg.
Calculate the molar mass and identify the compound. The compound is:
a)C2H4
b)C3H6
c)C4H8
d)C5H10
e)C6H12
How is this problem worked out to get "c"...C4H8??? Do I use PV=nRT?...if so...how is it used for this problem?

PV=nRT

P = (749/760) atm.
V 0.102 L
solve for n. I get 0.004139
R = 0.08205 L*atm/mol*K
T = 273 + 23

# mols = g/molar mass.
you have mols and you have g. Solve for molar mass.
I get 56.
If it is a hydrocarbon, then 1C and 2H units is 14. 56/14 = 4 units of CH2
(CH2)4 = C4H8 OR you can just go down the list and calculate the molar mass of each of the answers.
a is 28, b is 42, 3 is 56, d is 70 and d is 84. Easy to pick out.

great! thank you!

so basically all that I had to do was 13/0.232? PV=nRT really had nothing to do with the problem then?

You used the ideal gas law PV=nRT to solve for the number of moles.

Mass= number of moles * molar mass

then you solved this for molar mass.

  1. 👍 0
  2. 👎 0
  3. 👁 70
asked by K

Respond to this Question

First Name

Your Response

Similar Questions

  1. chemistry

    Consider a sample of a hydrocarbon (a compound consisting of only carbon and hydrogen) at 0.959 atm and 298 K. Upon combusting the entire sample in oxygen, you collect a mixture of gaseous carbon dioxide and water vapor at 0.755

    asked by Jaxx on February 27, 2015
  2. CHEMISTRY

    I've been trying to do this problem but I would get confused and stuck.. Consider a sample of a hydrocarbon at 0.959 atm and 298 K. Upon combustion the entire sample in oxygen, you collect a mixture of gaseous carbon dioxide and

    asked by J on November 7, 2008
  3. Chemistry

    An unknown gaseous hydrocarbon consists of 85.63% carbon by mass. A 0.335 g sample of the gas occupies a volume of 0.107 L at STP. What is the identity of the gas?

    asked by Sarah on November 14, 2012
  4. organic chemistry

    In an eudiometer 20cm^3 of a gaseous hydrocarbon A is mixed with 150 cm^3 of oxygen. The combustion of A is initiated by an electric spark. After cooling and condensing the vapor the volume of the gaseous mixture is 110cm^3 of

    asked by angy on April 4, 2016
  5. organic chemistry

    In an eudiometer 20cm^3 of a gaseous hydrocarbon A is mixed with 150 cm^3 of oxygen. The combustion of A is initiated by an electric spark. After cooling and condensing the vapor the volume of the gaseous mixture is 110cm^3 of

    asked by angy on April 4, 2016
  6. Chemistry

    A gaseous compound is 30.4% nitrogen and 69.6% oxygen by mass. A 5.25-g sample of the gas occupies a volume of 1.00 L and exerts a pressure of 1.26 atm at -4.00°C. Which of these choices is its molecular formula?

    asked by Confuse on April 27, 2015
  7. Chemistry

    For each definition, find a corresponding term from the following list: alkane,alkene, alkyne, alcohol, ether, aldehyde, ketone, carboxylic acid, ester, amine, fuctional group, isomers. a. Organic compounds with identical

    asked by Elisabeth on July 20, 2010
  8. Chemistry

    For each definition, find a corresponding term from the following list: alkane,alkene, alkyne, alcohol, ether, aldehyde, ketone, carboxylic acid, ester, amine, fuctional group, isomers. a. Organic compounds with identical

    asked by Elisabeth on July 20, 2010
  9. Chemistry

    This is the first in a series of hw pages. If anyone would be able to help me with this one I think I would be able to complete the other 20 hw questions I have. Thanks to anyone that helps. For each definition, find a

    asked by Drew on July 20, 2010
  10. chemistry

    an organic iron compound consisting of Fe, C, H, and O was found to contain 51.043%C, 5.9886%H, 27.17%O, and 15.80%Fe. how many moles of each element are in 100g of the compound

    asked by Missy on September 14, 2010

More Similar Questions