An excess of sodium carbonate, Na, CO3, in solution is added to a solution containing 17.87 g CaCl2. After performing the experiment, 13.19 g of calcium carbonate, CaCO3, is produced. Calculate the percent yield of this reaction.

Approximately .

Explanation:

Balanced equation for this reaction:

.

Look up the relative atomic mass of elements in the limiting reactant, , as well as those in the product of interest, :

Calculate the formula mass for both the limiting reactant and the product of interest:

.

.

Calculate the quantity of the limiting reactant () available to this reaction:

.

Refer to the balanced equation for this reaction. The coefficients of the limiting reactant () and the product () are both . Thus:

.

In other words, for every of formula units that are consumed, of formula units would (in theory) be produced. Thus, calculate the theoretical yield of in this experiment:

.

Calculate the theoretical yield of this experiment in terms of the mass of expected to be produced:

.

Given that the actual yield in this question (in terms of the mass of ) is , calculate the percentage yield of this experiment:

.

the answer is b because, investigating whether another species of moth also drinks tears might be interesting, but it would not directly explain why this species of moth does.

to explain why this species of moth drinks tears, the scientist could ask: "what nutrients that moths need are in elephant tears? "

the scientist could experiment with moth repellent or oter ways to keep the moths away, but that would not answer his original question.