A 255-mL flask contains pure helium at a pressure of 746 torr. A second flask with a volume of 475 mL contains pure argon at a pressure of 726 torr. If the two flasks are connected through a stopcock and the stopcock is opened, what is the partial pressure of helium? If the two flasks are connected through a stopcock and the stopcock is opened, what is the partial pressure of argon?

If the two flasks are connected through a stopcock and the stopcock is opened, what is the total pressure?

Question

Cameron Schaefer

Chemistry

4 July, 16:29

A 255-mL flask contains pure helium at a pressure of 746 torr. A second flask with a volume of 475 mL contains pure argon at a pressure of 726 torr. If the two flasks are connected through a stopcock and the stopcock is opened, what is the partial pressure of helium? If the two flasks are connected through a stopcock and the stopcock is opened, what is the partial pressure of argon?

If the two flasks are connected through a stopcock and the stopcock is opened, what is the total pressure?

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Answers (1)

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Dax Long · Answer 1

pHe = 261 torr

pAr = 472 torr

P = 733 torr

Explanation:

The final volume for both gases is the same: V₂ = 255 mL + 475 mL = 730 mL

We can find the final partial pressure of each gas using Boyle's law.

He

P₁ * V₁ = P₂ * V₂

P₂ = P₁ * V₁ / V₂

P₂ = 746 torr * 255 mL / 730 mL = 261 torr

Ar

P₁ * V₁ = P₂ * V₂

P₂ = P₁ * V₁ / V₂

P₂ = 726 torr * 475 mL / 730 mL = 472 torr

The total pressure is the sum of the partial pressures.

P = 261 torr + 472 torr = 733 torr