Consider the following reaction.

3Ca(s) + N2(g) �¨ Ca3N2(s)
What is the theoretical yield in grams for the reaction if 10.50 g of calcium reacts with 5.50 g of N2?

Answer 12.93g

To find the theoretical yield in grams for the reaction, we need to follow a series of steps:

1. Write the balanced chemical equation for the reaction:
3Ca(s) + N2(g) ⟶ Ca3N2(s)

2. Convert the given masses of calcium (10.50 g) and nitrogen gas (5.50 g) to moles using their respective molar masses. The molar mass of calcium (Ca) is 40.08 g/mol, and the molar mass of nitrogen (N) is 28.02 g/mol.

For calcium:
moles of Ca = mass of Ca / molar mass of Ca
moles of Ca = 10.50 g / 40.08 g/mol

For nitrogen:
moles of N2 = mass of N2 / molar mass of N2
moles of N2 = 5.50 g / 28.02 g/mol

3. Determine the limiting reactant. The limiting reactant is the reactant that is completely consumed and determines the maximum amount of product that can be formed. To find the limiting reactant, we need to compare the moles of each reactant from step 2.

The balanced equation shows that the stoichiometric ratio between calcium and nitrogen gas is 3:1. This means we need three moles of calcium for every one mole of nitrogen gas.

Let's compare the moles:
moles of Ca / 3 = moles of N2

If the ratio is less than 1, then the limiting reactant is calcium. If the ratio is greater than 1, the limiting reactant is nitrogen gas.

4. Calculate the moles of the product (Ca3N2) formed using the moles of the limiting reactant (in this case, calcium). Follow the stoichiometry of the balanced equation to determine the moles of product formed.

moles of product = (moles of Ca / 3) * 1

5. Convert the moles of the product to grams using the molar mass of the product, which is 148.25 g/mol.

mass of product = moles of product * molar mass of Ca3N2

Now you can perform the calculations. After determining the limiting reactant, the moles of the product and the mass of the product can be calculated.

Note: It is good practice to round the final answer to the appropriate number of significant figures, but for the sake of this explanation, we will leave it in the calculated form.