Amixture of helium and oxygen is used in scuba diving tanks to prevent ""the bends"". 46 l helium and 12 l oxygen are combined at 25°c and 1.0 atm in a tank with a total volume of 5.0 l. determine the partial pressures of he and oxygen and the total pressure in the tank.

Answer

given,

For helium

Volume,V = 46 L

Pressure,P = 1 atm

Temperature,T = 25°C  =  273 +25 = 298 K

R=0.0821 L . atm /mole.K

n₁ = ?

number of moles

we know

P V = n R T

  n₁ = 1.89 moles

For oxygen

Volume,V = 12 L

Pressure,P = 1 atm

Temperature,T = 25°C  =  273 +25 = 298 K

R=0.0821 L . atm /mole.K

n₂ = ?

number of moles

we know

P V = n R T

  n₂ = 0.49 moles

Total volume of tank = 5 L

temperature of tank = 298 K

Partial pressure of helium

     P₁ = 9.25 atm

Partial pressure of oxygen

    P₂ = 2.39 atm

total pressure

    P = P₁ + P₂

    P = 9.25 + 2.39

    P = 11.64 atm

80cm/s.

24cm/s.

53.3cm/s.