Final answer:
Calcium oxide is in excess by 6.0 g. The mass of calcium carbide produced is 20.53 g.
Step-by-step explanation:
To determine which reactant is in excess, we need to calculate the moles of each reactant. The molar mass of CaO is 56.08 g/mol and the molar mass of carbon is 12.01 g/mol. Using these molar masses, we find that there are 0.321 moles of CaO and 0.998 moles of carbon. From the balanced equation, we can see that the ratio of CaO to C is 1:3. Since there is less CaO than the required amount in the reaction, CaO is the limiting reactant and carbon is in excess. Therefore, the reactant in excess is carbon by a mass of 6.0 g.
To calculate the mass of calcium carbide (CaC₂) produced, we need to use the stoichiometry of the balanced equation. From the equation, we can see that 1 mole of CaO reacts to produce 1 mole of CaC₂. The molar mass of CaC₂ is 64.10 g/mol. Therefore, the mass of CaC₂ produced is 0.321 moles * 64.10 g/mol = 20.53 g. Rounded to two decimal places, the mass of CaC₂ produced is 20.53 g.