A gaseous mixture at a total pressure of 1.50 atm contains equal molar amounts of He, Ne, and Ar. At constant temperature CO2 gas is added to the mixture until the total pressure is 3.00 atm. Which of the following is a correct statement concerning partial pressures after the CO2 addition?
a. the original partial pressures of He, Ne, and Ar have been cut in half
b. the partial pressure of CO2 is three times that of Ne
c. all four gases have equal partial pressures
d. the partial pressure of Ar has doubled
a. the original partial pressures of He, Ne, and Ar have been cut in half
b. the partial pressure of CO2 is three times that of Ne
c. all four gases have equal partial pressures
d. the partial pressure of Ar has doubled
the original partial pressures of He, Ne, and Ar have been cut in half
the partial pressure of CO2 is three times that of Ne
all four gases have equal partial pressures
the partial pressure of Ar has doubled
A mixture of gases contains twice as many moles of As as Kr. If 0.300 mol of Xe is added to this mixture, the pressure increases from 1.26 atm to 1.47 atm. how many moles of Ar are in the mixture?
To answer this question, we need to understand the concept of partial pressure and how gases behave when they are mixed together.
Partial pressure is the pressure a gas would exert if it occupied the same volume alone, at the same temperature. In a mixture of gases, the total pressure is the sum of the partial pressures of each individual gas.
In the given scenario, we start with a gaseous mixture containing equal molar amounts of He, Ne, and Ar at a total pressure of 1.50 atm. CO2 gas is then added to the mixture until the total pressure is 3.00 atm.
Now, let's analyze the statements to determine the correct one:
a. The original partial pressures of He, Ne, and Ar have been cut in half.
This statement is not correct because the partial pressures of the original gases are not necessarily cut in half. Adding CO2 to the mixture will increase the total pressure but not necessarily affect the partial pressures of the other gases.
b. The partial pressure of CO2 is three times that of Ne.
This statement may or may not be correct depending on the partial pressures of the gases. We cannot determine the partial pressure of CO2 solely based on the given information.
c. All four gases have equal partial pressures.
This statement is not correct. The initial mixture is composed of three gases, and adding CO2 to the mixture will change the relative partial pressures of the different gases.
d. The partial pressure of Ar has doubled.
This statement is correct. Since the total pressure doubles when CO2 is added, the partial pressure of each gas must also double to maintain the same ratio of gas pressures. Since the gases are initially in equal molar amounts, the partial pressure of Ar would double.
Therefore, the correct statement is option d. The partial pressure of Ar has doubled after the CO2 addition.
Why don't you try calculating it and see what happens.
Total P = 1.5 atm, assume any volume (but always use the same one---1 L is the most convenient) and calculate n = mols gas. Since He, Ne, and Ar are equimolar, divide n/3 will be the mols of each of He, Ne, and Ar.
Then introduce CO2 (You are putting 1.5 atm CO2 in, keep the same conditions) and calculate mols CO2, then pressure of CO2. Then you will know the answer. I can help you through if you get stuck.