A 20.29-gram sample of impure magnesium carbonate is completely decomposed at 1000.°C in a previously evacuated 2.00-L reaction vessel. After the reaction was complete, the solid residue (consisting only of MgO and the original impurities) had a mass of 15.90 grams. Assume that no other constituent of the sample produced a gas and that the volume of any solid was negligible compared with the gas volume. (a) How many grams of CO2 were produced? (b) What was the pressure of the CO2produced? (c) What percent of the original sample was magnesium carbonate