You have a sample of 0.25 mol of unknown gas at stp. can you predict the volume of the gas, even if you don’t know the identity of the gas ? can you predict the mass of the sample ? explain.

a. 5.6 L

b. can be find without given mass or Molar mass

Explanation:

Data given:

mole of unknown gas = 0.25 mol

volume of gas = ?

mass of the sample = ?

Solution:

Yes we can find volume of the gas by using its amount of moles.

To find the volume of the gas at STP the following formula can be used

            no. of moles = volume of gas / molar volume

Rearrange the above formula

           volume of gas = no. of moles x molar volume . . . . . (1)

Where

molar mass of gas = 22.4 L/mol

Put values in equation 1

        volume of gas = 0.25 mol x 22.4 (L/mol)

       volume of gas = 5.6 L

So the volume of gas is 5.6 L.

Q. Can you predict the mass of the sample?

To find mass of the gas we must know the molar mass of gas.

if we Know the molar mass of gas the by using ideal gas equation we can find mass of unknown gas

ideal gas equation

          PV = nRT . . . . . . .(1)

where

n = m/M . . . . . . (2)

by combining equation 1 and 2 we get following equation

          PV = m/MRT . . . . . . .(3)

Now by rearranging equation 3 we can find mass of gas or Molar mass of gas. but one value must be given.

most historians agree that gabriel mouton, the vicar of st. paul’s church in lyons, france, is the “founding father” of the metric system. he proposed a decimal system of measurement in 1670. mouton based it on the length of one minute of arc of a great circle of the earth (now called a nautical mile, 1852 meters). he also proposed the swing-length of a pendulum with a frequency of one beat per second as the unit of length (about 25 cm). a pendulum beating with this length would have been fairly easy to produce, thus facilitating the widespread distribution of uniform standards. over the years, his work was revised, improved, and extended by a number of french scientists.

the political sponsor of weights and measures reform in the french revolutionary national assembly was the bishop of autun, better known as talleyrand. under his auspices, the french academy appointed several committees to carry out the work of developing a usable system of weights and measures for france. one of the committees recommended a decimalized measurement system based upon a length equal to one ten-millionth of the length of a quadrant of the earth’s meridian (i.e., one ten-millionth of the distance between the equator and the north pole).

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