Question

Calculate the mass of 45.0 L of NH3 at 57.0° C and 900. mm Hg.

Answer 1

Answer:

Mass = 33.515 g

Explanation:

Given data:

Volume of ammonia = 45.0 L

Temperature = 57.0°C (57 +273 = 330 K)

Pressure = 900 mmHg

Mass of ammonia = ?

Solution:

Formula:

PV = nRT

We will use R = 62.364 (L * mmHg)/(mol * K) because pressure is given in mmHg.

900 mmHg × 45.0 L = n × 62.364L * mmHg/mol * K × 330 K

40500 mmHg.L = n ×  20580.12L * mmHg/mol

n= 40500 mmHg.L/ 20580.12L * mmHg/mol

n = 1.9679 mol

Mass of ammonia:

Mass = number of moles × molar mass

Mass = 1.9679 mol × 17.031 g/mol

Mass = 33.515 g

When we multiply or divide the values the number of significant figures must be equal to the less number of significant figures in given value.