The white paste that lifeguards rub on their nose to prevent sunburn contains zinc oxide, \(\mathrm{ZnO}(s),\) as an active ingredient. Zinc oxide is produced by burning zinc sulfide. $$ 2 \mathrm{ZnS}(s)+3 \mathrm{O}_{2}(g) \rightarrow 2 \mathrm{ZnO}(s)+2 \mathrm{SO}_{2}(g) $$ $$\begin{array}{l}{\text { a. What is the coefficient for sulfur dioxide? }} \\\ {\text { b. What is the subscript for oxygen gas? }} \\ {\text { c. How many atoms of oxygen react? }} \\ {\text { d. How many atoms of oxygen react? }} \\ {\text { the total number of sulfur dioxide }} \\ {\text { molecules? }}\end{array}$$

Stoichiometry is the branch of chemistry that deals with the quantitative relationships between the reactants and products in a chemical reaction. It allows chemists to calculate the amounts of substances needed or produced by a reaction.

Let's consider the chemical equation provided: \(2 \mathrm{ZnS}(s) + 3 \mathrm{O}_{2}(g) \rightarrow 2 \mathrm{ZnO}(s) + 2 \mathrm{SO}_{2}(g)\). This equation gives us important stoichiometric information. The coefficients (2 and 3) indicate the molar proportions of the reactants and products. By using stoichiometry, we can answer questions about the amount of reactants required to produce a certain amount of product, or vice versa.

For example, if we need to produce 4 moles of sulfur dioxide (\(\mathrm{SO}_{2}\)), we can use stoichiometry to determine that we'll need to start with 4 moles of zinc sulfide (\(\mathrm{ZnS}\)) and 6 moles of oxygen (\(\mathrm{O}_{2}\)).

Chemical reactions involve the breaking and forming of chemical bonds between atoms, leading to changes in the composition of matter. In a chemical reaction like the one provided, reactants (zinc sulfide and oxygen) are transformed into products (zinc oxide and sulfur dioxide).

For a chemical reaction to occur, particles of the reactants must collide with enough energy to break their existing bonds and form new ones. The simplified representation of this transformation is what we see as a chemical equation. During the reaction, the law of conservation of mass states that matter cannot be created or destroyed, so the mass of the reactants must equal the mass of the products.

Examining the reaction mechanism, reactant particles of \(\mathrm{ZnS}\) and \(\mathrm{O}_{2}\) must collide with sufficient energy for the reaction to take place, leading to the production of \(\mathrm{ZnO}\) and \(\mathrm{SO}_{2}\), which are the products of this particular chemical process.

The process of balancing chemical equations is essential to accurately reflect the law of conservation of mass. It ensures that the number of atoms for each element is the same on both sides of the equation, indicating that matter is conserved.

In the given equation, \(2 \mathrm{ZnS}(s) + 3 \mathrm{O}_{2}(g) \rightarrow 2 \mathrm{ZnO}(s) + 2 \mathrm{SO}_{2}(g)\), the balancing is already done for us. Each element has the same number of atoms on the reactant and product sides. For instance, there are 2 atoms of zinc, 6 atoms of oxygen, and 2 atoms of sulfur on both sides.

When balancing chemical equations, begin by balancing elements that appear only once on each side. Afterward, balance elements that are in multiple compounds, making sure to adjust coefficients, which should always be whole numbers. In the example provided, oxygen appears as both \(\mathrm{O}_{2}\) and a part of \(\mathrm{SO}_{2}\). It's balanced last because it is part of two different compounds, which is typically more complex.