Question

Write the balanced chemical equation for the reaction between hydrochloric acid and magnesium metal.

Short answer

Mg + 2HCl → MgCl₂ + H₂

Step-by-step solution

Identify Reactants and Products

Determine the reactants and the products of the chemical reaction.

Write the Unbalanced Equation

Write the unbalanced chemical equation using the chemical formulas of the reactants and products: Hydrochloric acid (HCl) + Magnesium (Mg) → Magnesium chloride (MgCl₂) + Hydrogen gas (H₂).

Balance the Equation for Magnesium and Chlorine

Balance the magnesium (Mg) and chlorine (Cl) atoms: Mg + 2HCl → MgCl₂ + H₂.

Confirm Hydrogen Balance

Check if the hydrogen atoms are also balanced: There are 2 hydrogen atoms on both sides of the equation.

Write the Final Balanced Equation

The final balanced chemical equation is: Mg + 2HCl → MgCl₂ + H₂.

Key concepts

Chemical Reaction

A chemical reaction occurs when two or more substances interact to form new substances with different properties. In our exercise, the chemical reaction happens between hydrochloric acid (HCl) and magnesium metal (Mg). This reaction is interesting because it involves the formation of new compounds - magnesium chloride (MgCl₂) and hydrogen gas (H₂). Reactions can be complex, but understanding the key players (reactants) and the outcome (products) is crucial.

Additionally, chemical reactions often involve

• Exchange of atoms.
• Formation of bonds.
• Release or absorption of energy.

Naming the reactants and products correctly and knowing their chemical formulas (like HCl for hydrochloric acid) lay the foundation for understanding and balancing chemical equations.

Hydrochloric Acid

Hydrochloric acid, referred to as HCl, is a strong acid commonly used in chemistry labs. It's composed of hydrogen (H) and chlorine (Cl) atoms. When HCl is dissolved in water, it splits into hydrogen ions (H⁺) and chloride ions (Cl⁻).

This property makes HCl highly reactive, particularly with metals like magnesium. During the reaction, HCl breaks down, and its hydrogen ions play a key role in producing hydrogen gas (H₂). This ability to donate H⁺ ions makes hydrochloric acid crucial in many chemical reactions, not only in labs but also in industries, including the production of batteries, photoflash bulbs, and fireworks.

Magnesium Metal

Magnesium (Mg) is a shiny, silvery-white metal known for its lightweight and strong properties. In the periodic table, magnesium is found in Group 2, which is the alkaline earth metals group. These metals are known for their reactivity, especially with acids.

When magnesium reacts with hydrochloric acid, it forms magnesium chloride (MgCl₂) and releases hydrogen gas (H₂). This reaction not only demonstrates the reactivity of magnesium but also produces useful compounds and gases. For example, magnesium chloride has applications in the food industry, and hydrogen gas is used as a clean energy source.
Magnesium's reactivity with acids like HCl is essential for various industrial and scientific purposes.

Balancing Equations

Balancing chemical equations is crucial for accurately representing the conservation of mass in chemical reactions. This principle states that atoms cannot be created or destroyed in a chemical reaction. Thus, the number of each type of atom on the reactants side (left) must equal the number on the products side (right).

For example, in the reaction between hydrochloric acid and magnesium:
1. Identify reactants and products: * Reactants: HCl and Mg* Products: MgCl₂ and H₂
2. Write the unbalanced equation:
Mg + HCl → MgCl₂ + H₂
3. Balance the equation by adjusting coefficients:
Mg + 2HCl → MgCl₂ + H₂. This ensures 1 Mg, 2 Cl, and 2 H atoms on both sides.
Checking science and math, balancing helps ensure accuracy in representing chemical reactions.

Chemical Formulas

Chemical formulas are shorthand representations of chemical compounds, showing the types and numbers of atoms involved. For instance, HCl stands for hydrochloric acid, where H represents hydrogen and Cl represents chlorine.

Understanding chemical formulas is essential for writing and balancing chemical equations. For example:

• Mg represents magnesium.
• MgCl₂ indicates a compound with one magnesium atom and two chlorine atoms.
• H₂ signifies two hydrogen atoms bonded together to form a molecule of hydrogen gas.

Recognizing these notations allows chemists to predict the outcomes of reactions and ensure the conservation of mass.
Properly writing and interpreting chemical formulas is a foundational skill in chemistry.