A mixture of 20.0 grams of CaO and BaO is placed in a 12.5 L vessel at 200oC with excess CO2 . The mixture is allowed to react to completion forming CaCO¬3 and BaCO3 .The pressure in the container after reaction is 220 torr. The solid carbonates are neutralized by adding 650.0 ml of 1.0M HCl at 20oC. The final temperature of the solution after reaction is 21.066 oC. A drop of phenolphthalein is added to the solution and it remains colorless. Assume the specific heat capacity of the solution is 4.18j/goC.

Substance ∆Hf (kJ/mol)
Ba+2(aq) -538.4
Cl- (aq) -167.4
Ca+2(aq) -543.0
H2O (l) -286
CO2(g) -393.5
HCl (aq) -167.2
CaCO3 (s) -1207
BaCO3 (s) -1213
Find the initial pressure of the CO2(g) and mass percents of BaO and CaO in the mixture.
The solution is then titrated with NaOH until the solution turns pink. This requires the addition of 275.0 ml of NaOH. Calculate the molarity of the NaOH.

To find the initial pressure of CO2 (g), we need to use the ideal gas law equation: PV = nRT.

Step 1: Calculate the number of moles of CO2 (g)
To find the number of moles of CO2 (g) present, we need to use the molar mass of CO2, which is 44.01 g/mol, and the mass of CaO and BaO in the mixture.

We are given that the mixture contains 20.0 grams of CaO and BaO. Let's assume the mass percent of CaO is x, and the mass percent of BaO is (100 - x).

The molar mass of CaO is 56.08 g/mol, and the molar mass of BaO is 153.33 g/mol.

Using the equation:
Mass of CaO = (mass percent of CaO / 100) * Total mass of the mixture
20.0 g = (x/100) * (20.0 g CaO + 20.0 g BaO)

Simplifying the equation:
20.0 g = (x/100) * 40.0 g
x = (20.0 g / 40.0 g) * 100
x = 50%

Therefore, the mass percent of CaO is 50%, and the mass percent of BaO is (100 - 50) = 50%.

The number of moles of CaO can be calculated as:
moles of CaO = (mass of CaO / molar mass of CaO)
moles of CaO = (20.0 g CaO / 56.08 g/mol CaO)

The number of moles of BaO can be calculated similarly:
moles of BaO = (mass of BaO / molar mass of BaO)
moles of BaO = (20.0 g BaO / 153.33 g/mol BaO)

Step 2: Calculate the total moles of CO2
Since the reaction is assumed to go to completion, the moles of CO2 released will be equal to the moles of CaO and BaO reacted. Therefore, the total moles of CO2 will be the sum of moles of CaO and BaO.

Total moles of CO2 = moles of CaO + moles of BaO

Step 3: Calculate the volume of the vessel:
Use the ideal gas law equation PV = nRT to find the volume of the vessel.

Given:
Pressure (P) = 220 torr (convert to atm: 1 atm = 760 torr)
Temperature (T) = 200°C + 273.15 = 473.15 K (convert to Kelvin)
R = 0.0821 L·atm/(mol·K) (Ideal gas constant)

V = nRT / P
V = (Total moles of CO2) * (R) * (T) / P

Step 4: Calculate the initial pressure of CO2
The initial pressure of CO2 is equal to the pressure in the vessel before the reaction took place.

Initial pressure of CO2 = 220 torr (convert to atm)

Now, you can substitute the values into the equation to find the initial pressure of CO2.

To calculate the molarity of NaOH used in the titration, we can use the equation:

Moles of NaOH = Molarity of NaOH * Volume of NaOH used (in liters)

Moles of NaOH can be calculated as half the moles of HCl used, as the chemical equation for the reaction is:

HCl + NaOH -> NaCl + H2O

Given:
Volume of NaOH used = 275.0 mL = 0.275 L
Moles of HCl used = (Volume of HCl used in liters) * (Molarity of HCl)

The moles of NaOH will be half the moles of HCl:
Moles of NaOH = (0.5) * Moles of HCl

Finally, the molarity of NaOH can be calculated by rearranging the equation and substituting the values:

Molarity of NaOH = Moles of NaOH / Volume of NaOH used