Asample of gas has a mass of 0.673g. its volume is 250.0ml at a temperature of 83 degrees c and a pressure of 747 torr. the sample is composed of which of the following gases?
(a) xe
(b)ar
(c)so3
(d)co2
(e)h2

Explanation:

Given data:

Mass of sample = 0.673 g

Volume = 250.0 mL (0.25 L)

Temperature = 83°C (273+83= 356 k)

Pressure = 747 torr (747/760 = 0.98 atm)

Gas type = ?

Solution:

PV = nRT

n = PV/RT

n = 0.98 atm× 0.25 L / 0.0821 atm. L/mol.K × 356 k

n = 0.245 / 29.23/mol

n = 0.01 mol

Number of moles = mass/ molar mass

Molar mass = 0.673 g /  0.01 mol

Molar mass = 67.3 g/mol

molar mass of  CO2 = 44 g/mol

molar mass of  H2 = 2.016 g/mol

molar mass of  SO3 = 80.066 g/mol

molar mass of  Ar = 40 g/mol

molar mass of  Xe = 131.3 g/mol

So non of these gases are present.

"you start with 15.67 g mgco3-xh2o, when heated and all the water is removed, you are left with 7.58 g mgco3 only.

therefore, you had 15.67 - 7.58 = 8.09g h2o  

moles of each :

7.58g mgco3 = ? moles = 7.58g / 83.4g/mole = 0.09moles  

8 09g h2o = ? moles = 8.09g / 18g/mole = 0.44moles  

molar ratio between the two by dividing both numbers by the smallest number :

0.09 / 0.09 = 1  

0.44 / 0.09 = 4.8  

mgco3-5h2o"