A sample consisting of various gases contains 3.2×10−6 mole fraction of radon. This gas at a total pressure of 34 atm is shaken with water at 30 ∘C. Calculate the molar concentration of radon in the water. Express your answer using two significant figures.

Respuesta :

Answer:

The molar concentration of radon is 4.38 x 10⁻⁶ mol.L⁻¹

Explanation:

Molar fraction = number of moles of a certain component / total number of moles

Partial pressure = Total pressure x molar fraction

Partial pressure = 34 atm x 3.2 x 10⁻⁶

Partial pressure = 1.09 x 10⁻⁴ atm

Considering radon as an ideal gas, PV = nRT

molar concentration = n/V

n/V = P/RT

n/V = 1.09 x 10⁻⁴ atm / 0.082 L.atm.mol⁻¹K⁻¹ x 303.15K

n/V = 4.38 x 10⁻⁶ mol.L⁻¹

Considering the Dalton's partial pressure and ideal gas law, the molar concentration of radon in the water is [tex]4.38x10^{-6} \frac{mol}{L}[/tex].

Dalton's law

The pressure exerted by a particular gas in a mixture is known as its partial pressure.

So, Dalton's law states that the total pressure of a gas mixture is equal to the sum of the pressures that each gas would exert if it were alone:

[tex]P_{T} =P_{A} +P_{B} +...+P_{n}[/tex]

where n is the amount of gases in the mixture.

Dalton's partial pressure law can also be expressed in terms of the mole fraction of the gas in the mixture. So in a mixture of two or more gases, the partial pressure of gas A can be expressed as:

[tex]P_{A} =x_{A} P_{T}[/tex]

Ideal gas law

An ideal gas is characterized by three state variables: absolute pressure (P), volume (V), and absolute temperature (T). The relationship between them constitutes the ideal gas law, an equation that relates the three variables if the amount of substance, number of moles n, remains constant and where R is the molar constant of gases:

P×V = n×R×T

Partial pressure of radon

In this case, you know:

[tex]x_{A} =[/tex] 3.2×10⁻⁶

[tex]P_{T}=[/tex] 34 atm

Replacing in the Dalton's law:

[tex]P_{A} =[/tex] 3.2×10⁻⁶ ×34 atm

[tex]P_{A} =[/tex] 1.088×10⁻⁴ atm

Molar concentration of radon in the water

Considering radon as an ideal gas, it is satisfied: P×V = n×R×T

The molar concentration of radon is [tex]\frac{n}{V}[/tex]

From ideal gas law:

[tex]\frac{n}{V} =\frac{P}{RxT}[/tex]

You know:

  • P=  1.088×10⁻⁴ atm
  • R= 0.082 [tex]\frac{atm L}{mol K}[/tex]
  • T= 30 C= 303 K

Replacing:

[tex]\frac{n}{V} =\frac{1.088x10^{-4} atm}{0.082\frac{atm L}{mol K}x303 K}[/tex]

[tex]\frac{n}{V} =4.38x10^{-6} \frac{mol}{L}[/tex]

Finally, the molar concentration of radon in the water is [tex]4.38x10^{-6} \frac{mol}{L}[/tex].

Learn more about

Ideal gas law:

https://brainly.com/question/4147359

Dalton's partial pressure:

brainly.com/question/25181467

brainly.com/question/14119417

Molar fraction = number of moles of a certain component / total number of moles

Partial pressure = Total pressure x molar fraction

Partial pressure = 34 atm x 3.2 x 10⁻⁶

Partial pressure = 1.09 x 10⁻⁴ atm

Considering radon as an ideal gas, PV = nRT

molar concentration = n/V

n/V = P/RT

n/V = 1.09 x 10⁻⁴ atm / 0.082 L.atm.mol⁻¹K⁻¹ x 303.15K

n/V = 4.38 x 10⁻⁶ mol.L⁻¹