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**Dalton’s law formula**, expressed as P_{Total} = P_{1} + P_{2} + P_{3} + … + P_{n}, states that the total pressure of a mixture of gases is equal to the sum of the partial pressures of the individual gases in the mixture. In this formula, P_{Total} represents the total pressure of the gas mixture, while P_{1}, P_{2}, P_{3}, and so on, represent the partial pressures of each individual gas in the mixture.

## Practice problems

### Problem #1

A cylinder is filled with a mixture of nitrogen, oxygen, and helium gases. The mixture exerts a total pressure of 12 atm on the cylinder wall. The partial pressures of nitrogen and oxygen are 2 atm and 3 atm, respectively. Calculate the partial pressure of helium.

**Solution**

Given data:

- Total pressure of the gas, P
_{Total}= 12 atm - Partial pressure of the nitrogen gas, P
_{1}= 2 atm - Partial pressure of the oxygen gas, P
_{2}= 3 atm - Partial pressure of the helium gas, P
_{3}= ?

Applying the formula:

- P
_{Total}= P_{1}+ P_{2}+ P_{3}+ … P_{n} - P
_{Total}= P_{1}+P_{2}+ P_{3}(Because, a mixture is made up of three gases) - 12 = 2 + 3 + P
_{3} - P
_{3}= 12 – 5 - P
_{3}= 7 atm

Therefore, the partial pressure of the helium gas is **7 atm**.

### Problem #2

In a solid container, there is a mixture of four gases with partial pressures of 4 atm, 3 atm, 5 atm, and 8 atm, respectively. Calculate the total pressure of the gas mixture.

**Solution**

Given data:

- Partial pressure of the gas 1, P
_{1}= 4 atm - Partial pressure of the gas 2, P
_{2}= 3 atm - Partial pressure of the gas 3, P
_{3}= 5 atm - Partial pressure of the gas 4, P
_{4}= 8 atm - Total pressure of the gas, P
_{Total}= ?

Applying the formula:

- P
_{Total}= P_{1}+ P_{2}+ P_{3}+ … P_{n} - P
_{Total}= P_{1}+P_{2}+ P_{3}+ P_{4}(Because, a mixture is made up of four gases) - P
_{Total}= 4 + 3 + 5 + 8 - P
_{Total}= 20 atm

Therefore, the total pressure of the gas is **20 atm**.

### Problem #3

A container is filled with a mixture of hydrogen and argon gases. If the total pressure of the mixture is 9 atm and the partial pressure of hydrogen gas is 6 atm, calculate the partial pressure of argon gas.

**Solution**

Given data:

- Total pressure of the gas, P
_{Total}= 9 atm - Partial pressure of the hydrogen gas, P
_{1}= 6 atm - Partial pressure of the argon gas, P
_{2}= ?

Applying the formula:

- P
_{Total}= P_{1}+ P_{2}+ P_{3}+ … P_{n} - P
_{Total}= P_{1}+P_{2}(Because, a mixture is made up of two gases) - 9 = 6 + P
_{2} - P
_{2}= 9 – 6 - P
_{2}= 3 atm

Therefore, the partial pressure of the argon gas is **3 atm**.

### Problem #4

A container is filled with five gases that exert a total pressure of 24 atm on the container’s walls. The partial pressures of four of the gases are 2 atm, 5 atm, 6 atm, and 8 atm, respectively. What is the partial pressure of the fifth gas?

**Solution**

Given data:

- Total pressure of the gas, P
_{Total}= 24 atm - Partial pressure of the gas 1, P
_{1}= 2 atm - Partial pressure of the gas 2, P
_{2}= 5 atm - Partial pressure of the gas 3, P
_{3}= 6 atm - Partial pressure of the gas 4, P
_{4}= 8 atm - Partial pressure of the gas 5, P
_{5}= ?

Applying the formula:

- P
_{Total}= P_{1}+ P_{2}+ P_{3}+ … P_{n} - 24 = 2 +5 + 6 + 8 + P
_{5}(Because, a mixture is made up of five gases) - 24 = 21 + P
_{5} - P
_{5}= 24 – 21 - P
_{5}= 3 atm

Therefore, the partial pressure of the fifth gas is **3 atm**.

## Related

- Boyle’s law formula
- Charles law formula
- Gay-Lussac’s law formula
- Avogadro’s law formula
- Ideal gas law formula
**Dalton’s law formula**- Henry’s law equation
- Combined gas law formula

## External links

- Dalton’s Law of Partial Pressures — Overview & Calculation – Expii
- Dalton’s law of partial pressure (article) – Khan Academy
- Gas Behavior – Florida State University
- Dalton’s Law (Law of Partial Pressures) – Chemistry LibreTexts
- Daltons Law – an overview – ScienceDirect
- Dalton’s law – Wikipedia
- Partial Pressure Calculator – Omni Calculator
- Dalton’s Law of Partial Pressure | Formula & Examples – Study.com
- Dalton’s Law of Partial Pressure | Gas Laws – ChemTalk
- Partial Pressure Mole Fraction – Gas Phase – MCAT Content – Jack Westin
- Dalton’s Law of Partial Pressures – Worked Problem – ThoughtCo
- What is the equation for Dalton’s law of partial pressure? – Socratic
- Dalton’s Law: Partial Pressure (Simplified) – Pearson
- Gas Law – Dalton’s Law and other partial pressure problems – ChemTeam
- Total and Partial Pressure – Dalton’s Law of Partial Pressures – The Engineering ToolBox
- Dalton’s law Formula – SoftSchools.com
- Dalton’s Law of Partial Pressure – Definition and Examples – Science Notes and Projects
- Dalton’s Law of Partial Pressures – Chemistry Steps
- Dalton’s Law: Statement, Formula, and Example Problems – Chemistry Learner
- Dalton’s law | Definition & Facts – Britannica
- How to Calculate Partial Pressures Using Dalton’s Law – Dummies
- How to Calculate Partial Pressure: Step-by-Step Solution – wikiHow

Deep

Learnool.com was founded by Deep Rana, who is a mechanical engineer by profession and a blogger by passion. He has a good conceptual knowledge on different educational topics and he provides the same on this website. He loves to learn something new everyday and believes that the best utilization of free time is developing a new skill.