posted by .

I got think I got the following questions almost figured, but I just want someone to make sure that I am correct.

1) The whole experiment involves using the ideal gas law to predict the molar mass of an unknown liquid. The formula is molar mass of liquid = gR(0.0821)T(temperature in Kelvins) divided by Pressure(atm) multiplied by Volume (liters).

A student did not dry the erlenmeyer flask before weighing it. As a result of this error, would the molar mass be higher or lower than the correct value?
I said that the molar mass would be higher due to there is a greater difference in when one has to subtract the mass of the flask from the mass of the flask with the condensed liquid, there would be a greater difference and the mass of the substance would be calculated to be higher.

2) A student added 0.1mL of unknown liquid rather than 6mL to a 125mL flask. What effect would this action have on the calculated molar mass?

I said that there would be no difference because the volume of the flask is what the volume of the gas will be equal to.

  • Chemistry -

    I don't know exactly how the experiment was conducted but I think 1 is right. For 2, however, I think the results must be either too high or too low (but see the note below). If too little liquid is placed in the flask that means that vapor cannot fill the flask so your second weighing weighs all of the vapor produced and some air also. That means the mass of the vapor is too small which will lead to low results. Note: That answer assumes that 0.1 mL doesn't provide enough sample to fill the flask with vapor. If it did the result would not be changed.

Respond to this Question

First Name
School Subject
Your Answer

Similar Questions

  1. Chem (Help!)

    I really need help answering these questions. A sample of CO2 gas with a mass of 0.30 g is placed in a 250 mL container at 400 K. What is the pressure in atmospheres exerted by this gas?
  2. chemistry

    I'm stumped again :( the question is - A gas sprayed from an aerosol can effuses 5.06 times slower than oxygen.If the molar mass of oxygen is 32.g/mol, what is the molar mass of the unknown gas?
  3. 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. …
  4. Chemistry

    It takes bromine vapor 4.73 min to effuse through a pinhole of a container. How long will it take CH4 gas to effuse under the same temperature and pressure?
  5. chemistry

    mass= 3.8721g temperature= 102 degrees Celsius volume= 156ml atmospheric pressure= 755.0 mm Hg calculate the molar mass using the ideal gas law
  6. chemistry

    4. Use the pressure of the butane gas (your answer from question #3 above), along with the temperature and volume recorded in the lab, to determine the moles of butane gas collected in the lab. You will use the ideal gas law (and the …
  7. College Chemistry

    Using the molar volume (STP) or the ideal gas law equation, determine the molar mass,g/mole, of each of the following. A: 11.2g of a gas that has a volume of 1.50Lat STP?
  8. chemistry

    472 mL of H2 gas was collected over water when 1.256 g of Zn reacted with excess HCl. The atmospheric pressure during the experiment was 754 mm Hg and the temperature was 26 degrees C. A. Write the balanced chemical equation (I have …
  9. Chemistry

    Using molar volume (STP) or the ideal gas law equation, determine the molar mass, g/mole, of each of the following:1.)11.1g of a gas that has a volume of 1.50L at STP. 2.) 0.742g of a gas that has a volume 860mL at 1.28atm and 18∘C. …

    The mass of an erlenmeyer flask is 78.639g and the mass of the flask and water is 327.039. If the density of water is 1 g/ml then what is the true volume of the flask?

More Similar Questions