# chemistry

posted by .

A 5.000 g sample of a mixture which contains MgCO3 and sand (SiO2) was heated for 2.30 hours until no further reaction occurred. It was then cooled and the residue, which contained MgO and unchanged sand, was weighed. The reaction is: MgCO3(s)  MgO(s) + CO2(g). The residue remaining (minus the CO2 which was completely driven off) weighed 3.397 grams. Calculate the percent, by weight, of MgCO3 in the original sample.

• chemistry -

MgCO3 + SiO2 + heat ==> MgO + CO2 + SiO2

Loss in mass = 5.000-3.397 = 1.603 g = mass CO2.
mols CO2 = 1.603/44 = ?
mols MgCO3 = the same (from the equation).
mass MgCO3 = mols x molar mass
%MgCO3 = (mass MgCO3/mass sample)*100 = ?

• chemistry -

THANK YOU SO MUCH!!

## Similar Questions

1. ### AP Chemistry

A 21.0054 g sample of impure magnesium carbonate was heated to complete decomposition according to the equation MgCO3(s) → MgO(s) + CO2(g) . After the reaction was complete, the solid residue (consisting of MgO and the original …
2. ### Chemistry

Suppose that you calculated the mass percent of sand in the mixture to be 42%, though the original mixture really contained only 35% sand. How could you explain these results?
3. ### AP chemistry

A 22.709 g sample of impure magnesium carbonate was heated to complete decomposition according to the equation MgCO3(s) → MgO(s) + CO2(g). After the reaction was complete, the solid residue (consisting of MgO and the original …
4. ### Chemistry

A 28.4288 g sample of impure magnesium car- bonate was heated to complete decomposition according to the equation MgCO3(s) ! MgO(s) + CO2(g) . After the reaction was complete, the solid residue (consisting of MgO and the original impurities) …
5. ### AP Chemistry

A 28.4858 g sample of impure magnesium carbonate was heated to complete decomposition according to the equation MgCO3(s)→MgO(s) + CO2(g).After the reaction was complete, the solid residue (consisting of MgO and the original impurities) …
6. ### Chemistry

A 28.4378 g sample of impure magnesium carbonate was heated to complete decomposition according to the equation MgCO3(s) → MgO(s) + CO2(g). After the reaction was complete, the solid residue (consisting of MgO and the original …
7. ### chemistry

a student tried to separate a mixture of sand and red-colored water using a suction filtration apparatus. From a mixture of 10.0g of sand and 90.0g of water, the student recovered 9.5g of sand. what was the percent recovery of sand …
8. ### Chemistry

A 0.60 g sample consisting of only CaC2O4 & MgC2O4 is heated at 5000C, converting the two salts of CaCO3 and MgCO3 . The sample then weighs 0.465 g. If the sample had been heated to 9000C, where the products are CaO & MgO, what would …
9. ### chemistry

A 21.8603 g sample of impure magnesium carbonate was heated to complete decomposition according to the equation MgCO3(s) → MgO(s) + CO2(g). After the reaction was complete, the solid residue (consisting of MgO and the original …
10. ### Chemistry

What is the percentage of sand (SiO2) in a 2.88g of a mixture If 1.93 of sand was recovered upon separation?

More Similar Questions