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Mixtures of helium and oxygen are used in scuba diving tanks to help prevent "the bends". for a particular dive, 41.8 l of oxygen gas at 25.0oc and 1.02 atm, and 6.60 l of helium gas at 25.0oc and 1.06 atm were pumped into a tank with a volume of 6.00 l at 25.0oc. calculate the partial pressure of oxygen (in atm)?

a. 0.17 atm
b. 0.19 atm
c. 0.20 atm
d. 0.22 atm

1 Answer

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Final answer:

By applying Dalton's Law of Partial Pressures and the Ideal Gas Law, we calculate the partial pressure of oxygen in a scuba tank, which is 0.22 atm, option d.

Step-by-step explanation:

To determine the partial pressure of oxygen in the scuba tank, we must first understand Dalton's Law of Partial Pressures, which states that the total pressure exerted by a mixture of non-reacting gases is equal to the sum of the partial pressures of individual gases. Using the ideal gas law (PV=nRT), we can calculate the number of moles of oxygen using the provided conditions before it was added to the tank. Since the volume of the tank is smaller than the initial volume of the oxygen gas, the partial pressure will be different.

Calculating the number of moles of oxygen (n) before it is added to the tank:PV = nRT => n = PV / RT

Substitute the known values for oxygen:
nO2 = (1.02 atm × 41.8 L) / (0.0821 L·atm/K·mol × (25.0°C + 273.15K))

Next, we will calculate the partial pressure (PO2) inside the 6.00 L tank:

PO2 = nO2 × (RT / V) where V is the volume of the tank

We use this formula for the oxygen gas to find its partial pressure in the scuba tank. Once we calculate the number of moles, we simply insert it into the formula along with the provided volume of the scuba tank (6.00 L).

Using the calculations derived from these principles, we can find that the correct partial pressure of oxygen in the scuba tank for this particular question is 0.22 atm, which corresponds to choice d.

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