An amount of \(0.3\) mole of \(\mathrm{SrCl}_{2}\) is mixed with \(0.2\) mole of \(\mathrm{K}_{3} \mathrm{PO}_{4}\). The maximum moles of \(\mathrm{KCl}\) which may form is (a) \(0.6\) (b) \(0.5\) (c) \(0.3\) (d) \(0.1\)

Understanding balanced chemical equations is essential for solving stoichiometry problems. A balanced chemical equation respects the law of conservation of mass, which states that matter cannot be created or destroyed in a chemical reaction. To balance an equation, one must ensure the same number of atoms of each element is present on both the reactant and the product sides.

In the given exercise, the balanced chemical equation was critical for correctly solving the problem. When \(\mathrm{SrCl}_{2}\) reacts with \(\mathrm{K}_{3} \mathrm{PO}_{4}\), the equation must be balanced to reflect the stoichiometry, which shows that one molecule of \(\mathrm{SrCl}_{2}\) reacts with two molecules of \(\mathrm{K}_{3} \mathrm{PO}_{4}\) to produce one molecule of \(\mathrm{Sr}_{3}(\mathrm{PO}_{4})_{2}\) and six molecules of \(\mathrm{KCl}\). This ratio is crucial for determining the correct amount of products formed in the reaction.

In a chemical reaction, the limiting reactant, or limiting reagent, is the substance that is totally consumed first, thus determining the maximum amount of product that can be formed. The concept resembles a recipe—imagine making sandwiches with only a limited number of bread slices. No matter how much of the other ingredients you have, the sandwiches cannot exceed the number of available bread slices.

In the provided exercise, the limiting reactant calculation involved comparing the amount of reactants used with the stoichiometric coefficients from the balanced equation. To find which reactant is the limiting one, we use the given amounts and the reaction's stoichiometry. The reactant that yields the smallest amount of the desired product based on its stoichiometric ratio is identified as the limiting reactant, which in this case, was \(\mathrm{K}_{3} \mathrm{PO}_{4}\). Calculation of the limiting reactant is a crucial step to accurately predict product formation in chemical reactions.

The mole concept is a fundamental principle in stoichiometry, providing a bridge between the microscopic world of atoms and molecules and the macroscopic world we can measure. One mole is defined as Avogadro's number (approximately \(6.022 \times 10^{23}\)) of particles (atoms, molecules, ions, etc.). This concept allows chemists to count particles by weighing, as one mole of any substance will contain the same number of particles.

Applying the mole concept to the exercise, it helps to determine how much product will form from the reactants. Through the balanced equation and knowing the amounts of reactants in moles, we can calculate that 0.2 moles of the limiting reactant, \(\mathrm{K}_{3} \mathrm{PO}_{4}\), will yield 0.6 moles of \(\mathrm{KCl}\), using the stoichiometric relationships. The mole concept allows us to quantify and predict the outcomes of chemical reactions accurately.