a. Write a chemical equation for the reaction of solid iron with solid sulfur to form solid iron(II) sulfide. b. Write a chemical equation for the reaction of solid carbon with solid magnesium oxide to form carbon monoxide gas and magnesium metal.

Understanding how to balance chemical equations is essential when studying chemistry. A balanced chemical equation ensures that the same number of atoms of each element is present on both sides of the equation, aligning with the law of conservation of mass.

For instance, in the chemical reaction where solid iron (Fe) reacts with solid sulfur (S) to form solid iron(II) sulfide (FeS), one starts by writing the unbalanced equation:
Fe + S -> FeS
Initially, there is one atom of iron and one atom of sulfur on both sides, so this equation is already balanced. It illustrates that one iron atom combines with one sulfur atom to form one molecule of iron(II) sulfide.

In a more complex scenario, when solid carbon (C) reacts with magnesium oxide (MgO) to form carbon monoxide (CO) and magnesium metal (Mg), you would write the unbalanced equation as:
C + MgO -> CO + Mg
To balance this equation, one must ensure that there are equal numbers of carbon, oxygen, and magnesium atoms on both the reactant and product sides. By placing a coefficient of 2 before carbon and carbon monoxide, the balanced equation becomes:
2C + MgO -> 2CO + Mg
Here, two carbon atoms and one oxygen atom from magnesium oxide combine to form two molecules of carbon monoxide and one atom of magnesium.

A chemical reaction involves the transformation of one or more substances into different substances. During these reactions, the bonds between atoms are broken and new bonds are formed, resulting in the creation of new compounds with different properties.

For example, when iron reacts with sulfur, the atoms combine to form iron(II) sulfide via a synthesis reaction, a type of chemical reaction where two or more reactants combine to form a single product. Similarly, the reaction of carbon with magnesium oxide involves a single displacement reaction, where carbon displaces magnesium from its compound, forming carbon monoxide and free magnesium metal.

These transformations strictly follow the stoichiometry defined by the balanced equation, ensuring that each atom has a place in the products. Such reactions are fundamental in chemical studies as they reveal the behavior of elements and compounds under different conditions.

Stoichiometry is the calculation of the quantities of reactants and products involved in a chemical reaction. It is based on the balanced chemical equation and allows for predictions on the amounts of substances consumed and produced.

In balancing our equation for the reaction between carbon and magnesium oxide, the stoichiometry tells us that for every molecule of magnesium oxide that reacts, we need two atoms of carbon to produce two molecules of carbon monoxide and one atom of magnesium. This ratio of 2:1:2:1 is crucial for understanding how much reactant is needed to make a certain amount of product.

Practical Applications of Stoichiometry

Stoichiometry is not just academic; it has practical implications in real-world situations such as cooking, where ingredients must be mixed in the correct proportions, or in industrial chemical manufacturing, where it ensures that processes are cost-effective and materials are used efficiently.