Question

Write the formula for the missing reactant or product in each of the following chemical equations. a. \(\mathrm{CH}_{4}(g)+\mathrm{Cl}_{2}(g) \rightarrow+\mathrm{HCl}(g)\) b. \(\mathrm{CH}_{3} \mathrm{CH}_{2} \mathrm{CH}_{3}(g) \rightarrow \mathrm{CH}_{3} \mathrm{CHPCH}_{2}(g)+\) c. \(\mathrm{CHCl}_{3}(l)+\mathrm{Cl}_{2}(g) \rightarrow \mathrm{CCl}_{4}(l)+\)

Short answer

The missing reactants or products in the given chemical equations are: a. \(\mathrm{CH}_{3}\mathrm{Cl}(g)\) b. \(\mathrm{PH}_{3}(g)\) c. \(\mathrm{H}_{2}(g)\)

Step-by-step solution

First, we will identify the elements present in this chemical equation: Carbon (C), Hydrogen (H), and Chlorine (Cl). #Step 2: Balance the Equation#

To find the missing product in the equation, we will need to balance the equation. Count the number of each atom on both sides of the reaction and ensure they are equal. On the reactant side, there are 1 C, 4 H, and 2 Cl atoms. On the product side, we have an unknown product with 1 H and 1 Cl atom. In order to balance the equation, we should have 3 leftover Cl atoms and 3 H atoms in the missing product. The balanced product should be \(\mathrm{CH}_{3}\mathrm{Cl}\), with the balanced equation: \[ \mathrm{CH}_{4}(g)+\mathrm{Cl}_{2}(g) \rightarrow \mathrm{CH}_{3}\mathrm{Cl}(g) + \mathrm{HCl}(g) \] b. $\mathrm{CH}_{3} \mathrm{CH}_{2} \mathrm{CH}_{3}(g) \rightarrow \mathrm{CH}_{3} \mathrm{CHPCH}_{2}(g)+$ #Step 1: Identify the Elements#

First, we will identify the elements present in this chemical equation: Carbon (C), Hydrogen (H), and Phosphorus (P). #Step 2: Balance the Equation#

On the reactant side, we have 3 C, 8 H, and 0 P atoms. On the product side, we have 3 C, 5 H, and 1 P atom. The missing product should contain 3 H atoms to balance the equation. The balanced product will be \(\mathrm{PH}_{3}\), with the balanced equation: \[ \mathrm{CH}_{3}\mathrm{CH}_{2}\mathrm{CH}_{3}(g) \rightarrow \mathrm{CH}_{3}\mathrm{CHPCH}_{2}(g) + \mathrm{PH}_{3}(g) \] c. \(\mathrm{CHCl}_{3}(l)+\mathrm{Cl}_{2}(g) \rightarrow \mathrm{CCl}_{4}(l)+\) #Step 1: Identify the Elements#

First, we will identify the elements present in this chemical equation: Carbon (C), Hydrogen (H), and Chlorine (Cl). #Step 2: Balance the Equation#

On the reactant side, we have 1 C, 1 H, and 4 Cl atoms. On the product side, we have 1 C and 4 Cl atoms. The only remaining atom is H, so the missing product should be \(\mathrm{H}_{2}\), with the balanced equation: \[ \mathrm{CHCl}_{3}(l)+\mathrm{Cl}_{2}(g) \rightarrow \mathrm{CCl}_{4}(l) + \mathrm{H}_{2}(g) \]

Key concepts

Chemical Reactions

Chemical reactions are transformations where substances, termed as reactants, change into other substances called products. Understanding chemical reactions involves looking into what happens when these substances interact to form new materials.
In any chemical reaction, the structure of the reactants is altered, involving the breaking and forming of chemical bonds. This transformation typically involves an energy change, which can manifest as heat, light, or electrical energy.
Reactions are represented using chemical equations which symbolically show what happens to atoms during the reaction. A chemical equation includes symbols and formulas of reactants and products, and it's crucial for identifying the substances involved.
By studying chemical reactions, we can predict the products formed and understand the energy changes involved. This understanding helps in fields such as pharmaceuticals, agriculture, and energy production.

Reactants and Products

In the realm of chemistry, understanding reactants and products is key to grasping how a chemical reaction functions. Reactants are the starting materials that undergo change in a chemical reaction. They are present on the left side of a chemical equation.
Products are the substances that are formed as a result of a chemical reaction. They are found on the right side of the equation. For instance, in the reaction \(\mathrm{H}_2 + \mathrm{O}_2 \rightarrow \mathrm{H}_2\mathrm{O}\), hydrogen and oxygen are the reactants, while water is the product.
To predict what products will form, one must understand how molecules interact. Often, products have different physical and chemical properties compared to the reactants, showcasing the transformative power of chemical reactions.
Recognizing reactants and products enables chemists to balance equations, ensuring the law of conservation of mass is respected — that is, matter is neither created nor destroyed in a chemical reaction.

Stoichiometry

Stoichiometry simplifies understanding how different quantities of reactants are needed to form certain amounts of products. It is a concept rooted in the conservation of mass and mole concept. The principle behind stoichiometry is that the atomic mass of the reactants equals that of the products.
For chemical equations to be stoichiometrically correct, they need to be balanced. This means that there is the same number of each type of atom on both sides of the equation. Practicing stoichiometry involves knowing the molar ratios provided by the coefficients in a balanced chemical equation.
For instance, in the chemical equation \(\mathrm{N}_2 + 3\mathrm{H}_2 \rightarrow 2\mathrm{NH}_3\), stoichiometry tells us that one mole of nitrogen reacts with three moles of hydrogen to yield two moles of ammonia.
By understanding stoichiometry, students and chemists can make quantitative predictions about the yield of compounds, optimizing chemical processes in industries like pharmaceuticals and manufacturing.