Question

Determine and calculate the mass of 15.0 L of NH3, at 27 C and 900 mmHg.

Answer 1

To Find:

The mass of 15.0 L of NH₃ at 27°C and 900mm Hg.

Solution:

Firstly, convert the celsius (°C) to Kelvin (K).

Also, mm to atm.

=> K = C + 273

=> 27 + 273

=> 300k

We know that,

• 1 atm = 760mm Hg.

=> 900mm Hg = $\dfrac{900}{760}$mm Hg.

To find the number of moles of NH₃ = ?

Pv = nRT

=> $\dfrac{900}{760} \times 60 \times 15$

=> n × 0.0821 × 300

=> 17.76 = 24.63 n

=> n = 0.721 mol.

Now,

$\large n = \dfrac{mass}{molar \: mass}$

=> $0.721 = \dfrac{mass}{17}$

=> mass = 17 × 0.721

=> mass = 12.25g

Hence:

The mass of 15.0 L of NH₃ at 27°C and 900mm Hg is 12.25g (approx).