I'm working on a problem that says: a 4.00 gram sample of a mixture of cao and bao is placed in a 1.00 l vessel containing co2 at a pressure of 730 torr and a temperature of 25c. the co2 reacts with the cao and bao forming caco3 and baco3. when the reaction is complete, the pressure of the remaining co2 is 150 torr.
a) calculate the number of moles of co2 that have reacted.
i already did this part and got 0.0312 moles co2. i am stuck on the second part though.
b) calculate the mass percentage of cao in the mixture.
i know it will have something to do with grams of cao = x and grams bao = 4-x but i don't know how to solve from there. if anyone could that would be great !

explanation:

let the different atoms be x and y. each with four protons and same mass will be represented as follows.

mass number is number of protons + number of neutrons.

            and  

since, it is given that one has a negative charge while the other is neutral. therefore, there will be increase in number of protons and the atom will be represented as follows.

according to periodic table, mass number of beryllium is 9 and it has atomic number 4 so, the atoms will be and .  

the protons and neutrons will be located inside the nucleus whereas the electrons will be revolving around the nucleus.  

air

in a tire you fill a tire with air

then a couple days later you check the air pressure in the tire

hope this mark me brainliest