Copper reacts with nitric acid as shown in the balanced chemical equation \(3 \mathrm{Cu}+8 \mathrm{HNO}_{3} \rightarrow 3 \mathrm{Cu}\left(\mathrm{NO}_{3}\right)_{2}+2 \mathrm{NO}+4 \mathrm{H}_{2} \mathrm{O}\) If you react \(25.0 \mathrm{~g}\) of copper with an excess of nitric acid and produce \(7.24 \mathrm{~g}\) of \(\mathrm{NO}\), what is the percent yield for the reaction?

Understanding how to balance chemical equations is vital for analyzing reaction systems and calculating key information like the reactants needed and products formed. To balance an equation, ensure that the number of atoms of each element is equal on both the reactant and product sides.

For instance, in the provided exercise, copper (Cu) reacts with nitric acid (HNO₃) to produce copper(II) nitrate [Cu(NO₃)₂], nitric oxide (NO), and water (H₂O). Balancing the equation led to a ratio of 3 moles of Cu to 2 moles of NO. This stoichiometric ratio is crucial to determine the correct amount of reactants and products involved and for the calculation of the percent yield.

Stoichiometry is the quantitative relationship between reactants and products in a chemical reaction. It involves using balanced chemical equations to calculate the amounts of reactants needed and products formed.

By looking at the coefficients from the balanced equation, we can tell the ratio of moles of substances that react with each other. Stoichiometry lays the foundation for understanding chemical reactions quantitatively. The calculated ratio from the balanced equation applied in the solution—3:2 for Cu: NO—illustrates how stoichiometry is used to predict the amount of products formed from reactants.

The molar mass is the weight of one mole of a substance, measured in grams per mole (g/mol). It's equivalent to the sum of the atomic masses of the elements present in a chemical formula.

For example, nitric oxide (NO) has a molar mass of 30 g/mol because nitrogen (N) has an atomic mass of 14 u, and oxygen (O) has an atomic mass of 16 u. Calculating molar mass is essential for converting between the mass of a substance and the number of moles, which is used for finding both actual and theoretical yields in the reaction.

Moles provide a bridge between the microscopic particles and observable quantities of substances involved in a reaction. One mole is Avogadro's number (\(6.022 \times 10^{23}\)) of particles, be they atoms, molecules, or ions.

The theoretical yield is the maximum amount of product that can be obtained from a chemical reaction, assuming complete conversion of reactants. It is determined using stoichiometric calculations based on the balanced equation and the moles of reactants used. From the exercise, by calculating the moles of Cu and using the stoichiometric ratio, one can find the theoretical yield of NO. Percent yield is then found by comparing the actual yield, which is the amount actually produced in the laboratory, to the theoretical yield.