# chemistry

posted by .

A chemist weighed out 5.31 g of a mixture containing unknown amounts of BaO(s) and CaO(s) and placed the sample in a 1.50 L flask containing CO2(g) at 30.0°C and 750. torr. After the reaction to form BaCO3(s) and CaCO3(s) was completed, the pressure of CO2(g) remaining was 230. torr. Calculate the mass percents of CaO(s) and BaO(s) in the mixture.

• chemistry -

Use PV = nRT, substitute the numbers, and calculate mols CO2 initially, redo the formula and recalculate with new numbers to determine the moles CO2 remaining. The difference equals moles CO2 reacted.

Then let X = mass BaO
Let Y = mass CaO.
========================
X + Y = 5.31
(X/molar mass BaO) + (Y/molar mass CaO) = moles CO2 consumed (from above.)
Solve the two simultaneous equations for X and Y,

Then %BaO = (mass BaO/5.31)*100 = ??
%CaO = (mass CaO/5.31)*100 = ??
Post your work if you get stuck.

• chemistry -

i have a hard time understanding how to calculate the moles of CO2 remaining?
how do you use the PV=nRT for the remaining CO2?

• chemistry -

The problem states that after the CO2 has reacted with BaO and CaO, the remaining pressure is 230 torr. So plug that back into PV = nRT for P, along with the other numbers, and calculate a new n. Subtracting the two will give you the amount that reacted.

• chemistry -

for T, do I have to convert C to Kelvin? would they yield the same answers?

• chemistry -

X + Y = 5.31
(X/molar mass BaO) + (Y/molar mass CaO) = moles CO2 consumed (from above.)
Solve the two simultaneous equations for X and Y,

^I don't really understand this part either.

• chemistry -

why is moles of CO2 consumed equal to the combined moles of BaO and CaO?

## Similar Questions

1. ### Chem

A student placed a mixture of BaO and CaO in a 1.46L flask containing carbon dioxide at 35C and 746mmHg. After the reactions were complete she found that the CO2 pressure had dropped to 2.40 x 10^2mmHg. How many moles of CO2 were consumed …
2. ### Science

A chemist weighed out 5.16 g of a mixture containing unknown amunts of BaO(s) and CaO(s) and placed the sample in a 1.50-L flask containing CO2(g) at 30.0°C and 750. torr. After the reaction to form BaCO3(s) and CaCO3(s) was completed, …
3. ### Science

A chemist weighed out 5.16 g of a mixture containing unknown amunts of BaO(s) and CaO(s) and placed the sample in a 1.50-L flask containing CO2(g) at 30.0°C and 750. torr. After the reaction to form BaCO3(s) and CaCO3(s) was completed, …
4. ### Chemistry

If BaCO3 is placed in an evacuated flask, what partial pressure of CO2 will be present when the reaction reaches equilibrium?
5. ### Chemistry

CaO(s) reacts with SO2(g) according to the following equations: CaO9(s)+So2(g)--> CaSO3(g). A 8.85g mixture containing CaO(s) is placed in a 3.00-L container. The container is filled with SO2(g) to a pressure of 749 torr, at 20.0 …
6. ### Chemistry

The oxides of Group 2A metals (symbolized by M here) react with carbon dioxide according to the following reaction: MO(s) + CO2(g)  MCO3(s) A 2.85-g sample containing only MgO and CuO is placed in a 3.00-L container. …
7. ### AP Chemistry

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 …
8. ### AP Chemistry

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 …
9. ### Chemistry

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 …
10. ### chemistry

CaO(s) reacts with SO2(g) according to the following equations: CaO9(s)+So2(g)--> CaSO3(g). A 8.85g mixture containing CaO(s) is placed in a 3.00-L container. The container is filled with SO2(g) to a pressure of 749 torr, at 20.0 …

More Similar Questions