2 Stoichometry questions[please help] :)


I got a problem set of 58 questions, and I had trouble with this two. Can you help me?

If 10.0 g of carbon is combined with an exact, stoichiometric amount of oxygen (26.6 g) to produce carbon dioxide, what mass, in grams, of CO2 can be obtained?  That is, what is the theoretical yield of CO2?  [Molar masses:  C: 12.011    O2: 32.00    CO2: 44.01]

Burning coal and oil in a power plant produces pollutants such as sulfur dioxide, SO2.  The sulfur-containing compound can be removed from other waste gases, however, by the following reaction:
2 SO2(g)  +  2 CaCO3(s)  +  O2(g)    2 CaSO4(s)  +  2 CO2(g)
[Molar masses:  64.07            100.1          32.00            136.2              44.01]
(a) Name the compounds involved in the reaction.
(b) What mass of CaCO3 is required to remove 155 g of SO2?
(c) What mass of CaSO4 is formed when 155 g SO2 is consumed completely?

If 10.0 g of one reactant and 26.6 g of another are the exact stoichiometric amounts to produce a single product, when the reaction is complete you will have 0.0 g of each reactant and 10.0 g + 26.6 g = 36.6 g of the product of the reaction. It would not matter what the reactants are. Not knowing that 26.6 g is the stoichiometric amount of oxygen would require knowing the balanced reaction equation and the molar masses.
In this case, we know that one mole of C reacts with one mole of O2 to give one mole of CO2, and the amounts of reactants are about 0.832 moles:
10.0 g C / (12.011 g C/mole C) = 0.833 moles C
26.6 g O2 / (32.00 g O2/mole O2) = 0.831 moles O2
Theoretically 0.832 moles CO2 should form, or, in grams:
(0.832 moles CO2) X (44.01 g CO2/mole CO2) = 36.6 g CO2

For the reaction
2 SO2 + 2 CaCO3 + O2 --> 2 CaSO4 + 2 CO2,
155 g SO2, expressed as moles, would be
155 g SO2 / (64.07 g SO2/ mole SO2) = 2.42 moles SO2
The mole ratio for the reaction is 1:1, or 2 moles CaCO3 / 2 moles SO2,  so 2.42 moles CaCO3 would be required.
Expressed in grams, that would be
(2.42 moles CaCO3) X (100.1 g CaCO3 / mole CaCO3) = 242 g CaCO3
Similarly, for each mole of SO2, one mole of CaSO4 is produced, so from 155g (2.42 moles) of SO2, 2.42 moles of CaSO4 would form. Expressed in grams, what would that be?