I have multiple...

Question

1) If a metal ore contains 23.1% pure metal, how
many pounds of pure metal can be obtained
from 38 pounds of metal ore?
Answer in units of pounds.

2) For the reaction
3 F2 + Cl2 → 2 ClF3 ,
what is the maximum amount of ClF3
(92.4482 g/mol) which could be formed from
15.83 g of F2 (37.9968 g/mol) and 0.264 mol
of Cl2 (70.906 g/mol)?
Answer in units of mol.

- I already balanced the equation. My previous incorrect answers were 0.27, 0.528, and 0.53.

3) An ore contains Fe3O4 and no other iron. The
iron in a 56-gram sample of the ore is all
converted by a series of chemical reactions to
Fe2O3. The mass of Fe2O3 is measured to be
21.2 g. What was the mass of Fe3O4 in the
sample of ore?
Answer in units of g.

- Previous incorrect answers: 30.74, 40.52, 15.34, and 14.83.

4) The reaction of 9.9 grams of fluorine with
excess chlorine produced 3.3 grams of ClF3.
What percent yield of ClF3 was obtained?
Answer in units of %.

- Previous incorrect answers: 35.55 and 10.28

5) A 26.4501 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) had a mass of 17.435 g. Assuming
that only the magnesium carbonate had decomposed,
how much magnesium carbonate
was present in the original sample?
Answer in units of g.

6) An ore contains Fe3O4 and no other iron. The
iron in a 40.93 gram sample of the ore is all
converted by a series of chemical reactions to
Fe2O3. The mass of Fe2O3 is measured to be
30.7 grams. What was the percent Fe3O4 in
the sample of ore?
Answer in units of %.

- Previous incorrect answer: 52.46