Respuesta :
Answer: a) 211 mm Hg
b) 0.629 grams
Explanation:
According to Dalton's law, the total pressure is the sum of individual pressures.
[tex]p_{total}=p_1+p_2+p_3+p_4[/tex]
[tex]p_{total}[/tex] = total pressure = 750 mmHg
[tex]p_{CO_2}[/tex] = 124 mm Hg
[tex]p_{Ar}[/tex] = 218 mm Hg
[tex]p_{O_2}[/tex] = 197 mm Hg
[tex]p_{He}[/tex] = ?
[tex]750 mmHg=124 mm Hg+218 mm Hg+197 mm Hg+p_{He}[/tex]
[tex]p_{He}=211mmHg[/tex]
Thus the partial pressure of the helium gas is 211 mmHg.
b) According to the ideal gas equation:
[tex]PV=nRT[/tex]
P = Pressure of the gas = 211 mmHg = 0.28 atm (760mmHg=1atm)
V= Volume of the gas = 13.0 L
T= Temperature of the gas = 282 K
R= Gas constant = 0.0821 atmL/K mol
n= moles of gas= ?
[tex]n=\frac{PV}{RT}=\frac{0.28\times 13.0}0.0821\times 282}=0.157moles[/tex]
Mass of helium= [tex]moles\times {\text {molar mass}}=0.157\times 4=0.629g[/tex]
Thus mass of helium gas present in a 13.0-L sample of this mixture at 282 K is 0.629 grams
