Subject: Heat engineering Presented: Fazliddinov R. Accepted: Abdukarimov B

Subject: Heat engineering Presented: Abdurasulov A. Accepted: .

E
1-21

Topic: Ideal gas mixtures

• PLANS:
• Gas mixture.
• Dalton’s law (partial pressure).
• Mole Fractions of Gas Mixtures.

Gas mixture

• Gas mixture means that consist of two or a lot of gases. For examle: air, consisting of nitrogen, oxygen and a number of other gases, aqueous ammonia solutions, aqueous solutions of ethyl alcohol, various metal alloys.
• Also, it has partial pressure and mole fraction

Dalton’s law (partial pressure)

• The ideal gas law assumes that all gases behave identically and that their behavior is independent of attractive and repulsive forces. If volume and temperature are held constant, the ideal gas equation can be rearranged to show that the pressure of a sample of gas is directly proportional to the number of moles of gas present:
• P=n(RT/V)=n(constant)
• othing in the equation depends on the nature of the gas—only the amount.

Dalton’s law

• the total pressure exerted by a mixture of gases is the sum of the partial pressures of component gases. This law was first discovered by John Dalton, the father of the atomic theory of matter. It is now known as Dalton’s law of partial pressures. We can write it mathematically as:
• Pt=P1+P2+P3+⋅⋅⋅+Pi
• where Pt is the total pressure and the other terms are the partial pressures of the individual gases

Dalton’s law

Mole Fractions of Gas Mixtures

• The composition of a gas mixture can be described by the mole fractions of the gases present. The mole fraction (X) of any component of a mixture is the ratio of the number of moles of that component to the total number of moles of all the species present in the mixture (nt):
• The mole fraction is a dimensionless quantity between 0 and 1. If XA = 1.0, then the sample is pure A, not a mixture. If XA = 0, then no A is present in the mixture. The sum of the mole fractions of all the components present must equal 1.

Mole Fractions of Gas Mixtures

• To see how mole fractions can help us understand the properties of gas mixtures, let’s evaluate the ratio of the pressure of a gas A to the total pressure of a gas mixture that contains A. We can use the ideal gas law to describe the pressures of both gas A and the mixture: PA = nART/V and Pt = ntRT/V. The ratio of the two is thus
• Rearranging this equation gives
• PA = XAPt

Mole Fractions of Gas Mixtures

Questions

• What is the gas mixture?
• What is partial pressure?
• What is mole fraction?

Summary

• There are different presures of each gas in ideal gas mixtures. We can calculate it by Dalton’s law . Also, there is mole fraction. There are different moles each components. And then, we can calculate its amount of mole or pressure.

References:

• https://saylordotorg.github.io/text_general-chemistry-principles-patterns-and-applications-v1.0/s14-05-mixtures-of-gases.html
• https://ulodshi.ru/uz/gas-mixtures-heat-capacity-of-gases.html
• https://www.engineeringtoolbox.com/gas-mixture-properties-d_586.html
• https://www.google.com/search?q=ideal+gas+mixture+formula&rlz=1C1GCEA_enUZ883UZ883&oq=ideal+gas+mixture&aqs=chrome.0.69i59l2j69i57j0i67i650l2j0i131i433i512j0i512j69i60.25348j0j7&sourceid=chrome&ie=UTF-8