A special gas mixture is used in bacterial growth chambers which contains 5.00% by mass of CO2 and 95.0% O2. If the mole fraction of CO2 and O2 in the mixture is 0.0998 and 0.2340, respectively. What is the partial pressure in atmospheres of O2 and CO2 gases at a total pressure of 0.6880 atm?

3 answers

First, we can use the mole fractions to calculate the number of moles of each gas present in the mixture. Let's assume we have 100 grams of the mixture, then:

- Moles of CO2 = 0.05 x 100 / 44.01 = 0.1136 moles
- Moles of O2 = 0.95 x 100 / 32.00 = 2.9688 moles

Next, we can use the total pressure and mole fractions to calculate the partial pressures of each gas. The partial pressure of a gas is equal to its mole fraction times the total pressure. So:

- Partial pressure of CO2 = 0.0998 x 0.6880 atm = 0.0685 atm
- Partial pressure of O2 = 0.2340 x 0.6880 atm = 0.1608 atm

Therefore, the partial pressure of CO2 in the mixture is 0.0685 atm and the partial pressure of O2 is 0.1608 atm.
If the theoretical yield of PbCl2 is 16.547g from the reaction of 7.000g of NaCl with 50.400g of Pb(NO3)2. Calculate the % yield of PbCl2 if 12.788g of PbCl2 was actually obtained? (Atomic mass: Na-22.990 g/mol; Cl-35.453g/mol; 0-15.999g/mol; Pb-207.200 g/mol; N-14.007).
First, let's balance the equation:

2NaCl + Pb(NO3)2 → 2NaNO3 + PbCl2

From the balanced equation, the stoichiometry of the reaction is 2 moles of NaCl to 1 mole of Pb(NO3)2 to 1 mole of PbCl2.

We can calculate the number of moles of Pb(NO3)2 used in the reaction as follows:

50.400 g Pb(NO3)2 × 1 mol Pb(NO3)2 / 331.209 g Pb(NO3)2 = 0.1521 mol Pb(NO3)2

Therefore, the number of moles of PbCl2 that would be produced if the reaction went to completion is also 0.1521 mol (1:1 stoichiometry with Pb(NO3)2). The theoretical yield of PbCl2 can be calculated from the molar mass:

16.547 g PbCl2 × 1 mol PbCl2 / 278.104 g PbCl2 = 0.0595 mol PbCl2

Now we can calculate the percent yield:

Percent yield = actual yield / theoretical yield × 100%
= 12.788 g / 16.547 g × 100%
= 77.29%

Therefore, the percent yield of PbCl2 is 77.29%.