Question

Write chemical equations for each of the following sentences: a. Aluminum reacts with oxygen to produce aluminum oxide. b. Phosphoric acid, \(\mathrm{H}_{3} \mathrm{PO}_{4},\) is produced through the reaction between tetraphosphorus decoxide and water. c. Iron(III) oxide reacts with carbon monoxide to produce iron and carbon dioxide.

Short answer

a. 4Al + 3O2 → 2Al2O3b. P4O10 + 6H2O → 4H3PO4c. Fe2O3 + 3CO → 2Fe + 3CO2

Step-by-step solution

Write the reactants and products for aluminum reaction

Identify the reactants, which are aluminum (Al) and oxygen (O2), and the product, which is aluminum oxide (Al2O3).

Write the unbalanced chemical equation for aluminum reaction

The unbalanced chemical equation is: Al + O2 → Al2O3.

Balance the chemical equation for aluminum reaction

Balance the equation by ensuring the number of atoms of each element is the same on both sides: 4Al + 3O2 → 2Al2O3.

Write the reactants and products for phosphoric acid reaction

Identify the reactants, which are tetraphosphorus decoxide (P4O10) and water (H2O), and the product, which is phosphoric acid (H3PO4).

Write the unbalanced chemical equation for phosphoric acid reaction

The unbalanced chemical equation is: P4O10 + H2O → H3PO4.

Balance the chemical equation for phosphoric acid reaction

Balance the equation by ensuring the number of atoms of each element is the same on both sides: P4O10 + 6H2O → 4H3PO4.

Write the reactants and products for iron(III) oxide reaction

Identify the reactants, which are iron(III) oxide (Fe2O3) and carbon monoxide (CO), and the products, which are iron (Fe) and carbon dioxide (CO2).

Write the unbalanced chemical equation for iron(III) oxide reaction

The unbalanced chemical equation is: Fe2O3 + CO → Fe + CO2.

Balance the chemical equation for iron(III) oxide reaction

Balance the equation by ensuring the number of atoms of each element is the same on both sides: Fe2O3 + 3CO → 2Fe + 3CO2.

Key concepts

Chemical Reactions

A chemical reaction is a process where substances, known as reactants, transform into different substances called products. This transformation is characterized by the breaking and forming of bonds between atoms. For example, when aluminum reacts with oxygen to form aluminum oxide, it involves breaking the bonds in the elemental aluminum and oxygen molecules and forming new bonds in aluminum oxide. Chemical reactions can release or absorb energy, which can often be observed as heat, light, or sound. Understanding the nature of chemical reactions helps us to predict the products and energy changes involved.

Stoichiometry

Stoichiometry is the branch of chemistry that deals with the quantitative relationships between the reactants and products in a chemical reaction. It involves using balanced chemical equations to calculate the amounts of substances involved. For instance, in the balanced equation for the reaction between iron(III) oxide and carbon monoxide, \(\text{Fe}_2\text{O}_3 + 3\text{CO} \rightarrow 2\text{Fe} + 3\text{CO}_2\), the coefficients indicate that 1 mole of iron(III) oxide reacts with 3 moles of carbon monoxide to produce 2 moles of iron and 3 moles of carbon dioxide. Stoichiometry is crucial for determining the proportionate amounts needed for reactions and thereby preventing wastage of reactants.

Reactants and Products

In any chemical reaction, reactants are the starting substances that undergo change, while products are the new substances formed as a result of the reaction. For example: \ul\. Aluminum (\( \text{Al} \)) and oxygen (\( \text{O}_2 \)) are the reactants in the reaction forming aluminum oxide (\( \text{Al}_2\text{O}_3 \)). \Another example: Tetraphosphorus decoxide (\( \text{P}_4\text{O}_{10} \)) and water (\( \text{H}_2\text{O} \)) are reactants, and phosphoric acid (\( \text{H}_3\text{PO}_4 \)) is the product. Understanding which substances are reactants and which are products helps in writing balanced chemical equations, which are essential for accurately representing and predicting the outcomes of chemical reactions.

Law of Conservation of Mass

The Law of Conservation of Mass states that mass cannot be created or destroyed in a chemical reaction. This means that the total mass of reactants must equal the total mass of products. For a chemical equation to be balanced, the number of atoms of each element must be the same on both sides of the equation. For example, in the reaction \(\text{4Al} + \text{3O}_2 \rightarrow \text{2Al}_2\text{O}_3\), there are 4 aluminum atoms and 6 oxygen atoms on both sides of the equation. Balancing chemical equations ensures that the principle of the conservation of mass is upheld, making it fundamental for accurate stoichiometric calculations and understanding the nature of chemical reactions.