Question

Calculate to three significant digits the density of boron trifluoride gas at exactly and exactly . You can assume boron trifluoride gas behaves as an ideal gas under these conditions.

Answer 1

The given question is incomplete. The complete question is :

Calculate to three significant digits the density of boron trifluoride gas at exactly −5°C and exactly 1 atm . You can assume boron trifluoride gas behaves as an ideal gas under these conditions.

Answer: The density of boron trifluoride gas is 3.08 g/L

Explanation:

To calculate the relation of density and molar mass of a compound, we use the ideal gas equation:

PV=nRT

P = pressure = 1 atm

V = Volume

n = number of moles

R = gas constant =0.0821 Latm/Kmol

T = temperature = $-5^0C=(273-5)= 268K$

Number of moles (n) can be written as:

$n=\frac{m}{M}$

where, m = given mass

M = molar mass

$PV=\frac{m}{M}RT\\\\PM=\frac{m}{V}RT$

where,

$\frac{m}{V}=d$

where d = density

The relation becomes:

PM=dRT  

$d=\frac{PM}{RT}$

$d=\frac{1atm\times 67.82g/mol}{0.0821Latm/Kmol\times 268K}=3.08g/L$

Thus the density of boron trifluoride gas is 3.08 g/L