Answer:
Molar mass = 20 g/mol
Explanation:
Given data:
Volume of gas = 108 mL
Mass of gas = 77.96 mg (77.96/1000 = 0.08 g)
Pressure of gas = 1140 mmHg
Temperature of gas = 183°C
Molar mass of gas = ?
Solution:
First of all we will calculate the number of moles of gas.
PV = nRT
R = general gas constant = 0.0821 atm.L/ mol.K
Now we will convert the units and then we will put the values in formula.
Volume of gas = 108 mL× 1 L/1000 mL= 0.108 L
Pressure of gas = 1140 mmHg× 1 atm / 760 mmHg = 1.5 atm
Temperature of gas = 183+273 = 456 K
PV = nRT
1.5 atm ×0.108 L = n × 0.0821 atm.L/ mol.K ×456 K
0.162 atm.L = n ×37.44 atm.L/ mol
n = 0.162 atm.L/37.44 atm.L/ mol
n = 0.004 mol
Molar mass of gas:
Number of moles = mass/molar mass
0.004 mol = 0.08 g / molar mass
Molar mass = 0.08 g /0.004 mol
Molar mass = 20 g/mol
