# Question involving Gas Laws: A 6.0L flask

• Chandasouk
In summary, the ideal gas law is a fundamental equation in chemistry that relates pressure, volume, temperature, and number of moles for a gas. It is only an approximation for real gases, which have volume and experience intermolecular forces. The 6.0L flask is a standard volume often used in gas law problems, and changes in temperature and pressure affect the volume of a gas in this flask according to the ideal gas law. However, the ideal gas law can only be used for ideal gases, and more complex equations are needed for real gases.
Chandasouk
A 6.0L flask contains a mixture of methane, argon, and helium at 45C and 1.75atm. If the mole fractions of helium and Argon are 0.25 and 0.35, respectively, how many molecules of methane are present?

V = 6.0L

T=318.15K

Ptotal=1.75atm

mole fraction: XHe=0.25

XAr=0.35

XCH4=0.40

Because mole fractions always add up to 1

Then I used Partial Pressure formula

Partial Pressure of CH4 = 0.40 X 1.75atm = 0.7atm

Then Ideal gas law

n=PV/RT

n=(0.7atm)(6L)/(.o8206)(318.15K) = 0.16087 moles of CH4

0.16087 moles of CH4 X 6.022 x 1023 molecules = 9.69 X 10^22 molecules of methane?

Looks OK. Watch significant digits.

--
methods

Based on the given information, there are approximately 9.69 x 10^22 molecules of methane present in the 6.0L flask. This calculation was done using the ideal gas law, which relates the pressure, volume, temperature, and number of moles of a gas. The mole fractions of helium and argon were used to determine the partial pressure of methane, which was then used to calculate the number of moles and molecules of methane present in the flask. This calculation can be used to better understand the composition and behavior of gases in a given system.

## 1. What is the ideal gas law?

The ideal gas law is a fundamental equation in chemistry that describes the relationship between the pressure, volume, temperature, and number of moles of a gas. It is given by the equation PV = nRT, where P is the pressure, V is the volume, n is the number of moles, R is the ideal gas constant, and T is the temperature in Kelvin.

## 2. How does the ideal gas law relate to real gases?

The ideal gas law assumes that gases behave ideally, meaning they have no volume and experience no intermolecular forces. However, in reality, gases do have volume and experience intermolecular forces, so the ideal gas law is only an approximation for real gases. In certain conditions, such as low pressure and high temperature, real gases behave similarly to ideal gases and the ideal gas law can be used to make accurate predictions.

## 3. What is the significance of the 6.0L flask in gas law problems?

The 6.0L flask is a standard volume often used in gas law problems as it is a convenient size for laboratory experiments. It is used to represent the volume of a gas in a closed system, where the volume remains constant.

## 4. How do changes in temperature and pressure affect the volume of a gas in a 6.0L flask?

According to the ideal gas law, an increase in temperature or pressure will result in an increase in volume of a gas in a 6.0L flask, assuming the number of moles and the gas constant remain constant. This is because an increase in temperature or pressure causes the gas particles to move faster and occupy more space.

## 5. Can the ideal gas law be used for all gases?

The ideal gas law can only be used for ideal gases, which do not exist in reality. However, it can be used as an approximation for real gases under certain conditions, such as low pressure and high temperature. For real gases, more complex equations, such as the van der Waals equation, must be used to accurately describe their behavior.

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