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What is the pressure in bar of a 4.50 L tank with 3.35 moles of oxygen at 39.3 °C?

Given: \( R = 0.08314 \, \text{L・bar/mol・K} \)

Answer :

Answer:

19.3 bar

Explanation:

The ideal gas law allows us to calculate different characteristics of gases.

Ideal Gas Law

One way to calculate different values of gases we can use the ideal gas law. This law was named for the fact that it assumes gases behave "ideally." This means that the gases have perfectly elastic collisions and experience no intermolecular forces (IMFs). In equation form, this law is:

  • PV = nRT

In the equation, P is pressure, V is volume, n is moles, R is the gas constant, and T is the temperature in Kelvin. It is important to ensure that the units of the gas constant match the units of pressure that you are solving for.

Finding Pressure

To find pressure, we need to plug in the information we know and solve for P. The units of the gas constant we are given already match the pressure, so we do not need to convert. However, the temperature is given in °C not K. This means we need to convert; to do this, add 273 to °C.

  • 39.3 °C + 273 = 312.3K

Now, we can plug all of our information into the ideal gas law.

  • P · 4.50L = 3.35mol · 0.08314L・bar/mol・K · 312.3K

To find P, divide both sides by 4.50.

  • P = 19.33 bar

Since the question is based on measured values, we need to round according to significant figure rules. The measured values in the question have 3 sig figs, so our answer should also have 3. This means the pressure is 19.3 bar.

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