4. What is the mass of N2H4 gas in a 350.0 mL container at 50.0 °C, if the pressure of the gas is 885.0 torr?

0.36g

Explanation:

Given parameters and conversion to standard unit

 To solve this problem we must assume ideality

Volume of N₂H₄  =  350mL  = 0.35dm³

Temperature of container  = 50°C  = 50 + 273  = 323K

Pressure  = 885torr;

               760torr  = 1atm

               885torr  =   = 0.86atm

Unknown:

Mass of the compound  = ?

Solution:

The mass of the compound can be derived using the expression below;

         Mass = number of moles x molar mass

molar mass of N₂H₄ = 2(14) + 4(1)  = 32g/mol

To find the number of moles;

       PV  = nRT

          n  =

P is the pressure

V is the volume

R is the gas constant = 0.082atmdm³mol⁻¹K⁻¹

T is the temperature

         n  =   = 0.01mole

So,

    Mass  = 0.01 x 32  = 0.36g