A 1.00 L flask containing gas A at 5.00 atm is connected to a 4.00 L flask containing gas B at 1.00 atm. When the two gases are allowed to mix at constant temperature, what is the final pressure in the two-flask assemblage?

The final pressure in the two-flask assemblage is 1.8 atm

Explanation:

The given variables are

Flask 1 with gas A = 1.00 L at 5.00 atm

Flask 2 with gas B = 4.00 L at 1.00 atm

From the Daltons law of partial pressure which states that the total pressure of a given mixture of gases is equal to the sum of the partial pressures of the gases in the mixture

Ptotal = P₁ + P₂ + P₃

Final volume of both gases = 5.00 L

Boyle's law states that the pressure of a given mass of gas is inversely proportional to its volume

P₁·V₁ = P₂·V₂

Therefore their final pressure =

for gas A 1.00 L * 5.00 atm = 5.00 L * P₂

therefore P₂ = 1.00 atm

for gas B

1.00 atm * 4.00 L = P₂*5.00 L

Therefore P₂ = 4/5 atm

Total pressure P₂ for gas A + P₂ for gas B

1+4/5 atm or 1.8 atm