Question

Chloroform is a volatile liquid once commonly used in the laboratory but now being phased out due to its ozone depletion potential. If the pressure of gaseous chloroform in a flask is 195 mm Hg at 25°C and its density is 1.25 g/L, what is the molar mass of chloroform? A) 10.0 g/mol B) 76.3 g/mol C) 119 g/mol D) None of these

Answer 1

Answer : The correct option is, (C) 119 g/mol

Explanation :

To calculate the molar mass of chloroform we are using ideal gas equation:

$PV=nRT\\\\PV=\frac{w}{M}RT\\\\M=\frac{w}{V}\times \frac{RT}{P}\\\\M=\rho \times \frac{RT}{P}$

where,

P = pressure of gas = 195 mmHg = 0.256 atm    (1 atm = 760 mmHg)

V = volume of argon gas

T = temperature of gas = $25^oC=273+25=298K$

R = gas constant = 0.0821 L.atm/mole.K

w = mass of gas

$\rho$ = density of gas = 1.25 g/L

M = molar mass of chloroform = ?

Now put all the given values in the ideal gas equation, we get:

$M=1.25g/L\times \frac{(0.0821L.atm/mole.K)\times (298K)}{0.256atm}$

$M=119.4g/mol\approx 119g/mol$

Therefore, the molar mass of chloroform is, 119 g/mol.

Answer 2

The molar mass of chloroform if 195 mmHg at 25°C and density of 1.25 g/L is 119.5g/mol.

HOW TO CALCULATE MOLAR MASS:

• The molar mass of chloroform can be calculated by the following expression:

• PV = nRT

• PV = m/m.m × R × T

• M.m = m/v × RT/p

• M.m = ρ × RT/p

Where;

1. M.m = molar mass (g/mol)
2. ρ = density (g/L)
3. R = gas law constant (0.0821 Latm/molK)
4. T = temperature (K)
5. P = pressure (atm)

1. T = 25°C = 25 + 273 = 298K
2. P = 195 mmHg = 0.256atm

• M.m = 1.25 × (0.0821 × 298)/0.256

• M.m = 1.25 × 95.57

• M.m = 119.5g/mol

• Therefore, the molar mass of chloroform if 195 mmHg at 25°C and density of 1.25 g/L is 119.5g/mol.

Learn more at: https://brainly.com/question/22997914?referrer=searchResults