Question

Magnesium metal reacts with oxygen gas in a combination reaction. Write a balanced equation to describe this reaction.

Short answer

The balanced equation for the reaction is 2Mg + O2 -> 2MgO.

Step-by-step solution

Identify the Reactants

First, let's identify the reactants which are Magnesium metal and Oxygen gas. These are noted as Mg (for Magnesium) and O2 (for Oxygen gas).

Identify the Products

In a combination reaction involving a metal and oxygen, the product will be a metal oxide. In this case, it will be Magnesium Oxide, which is written as MgO.

Write the Unbalanced Equation

After identifying the reactants and products, we can write an unbalanced equation: Mg + O2 -> MgO.

Balance the Equation

Now we balance this equation. To balance the Oxygen atoms, we place a coefficient of 2 in front of MgO in the products side. But doing this imbalances the Magnesium atoms, so to balance these we also put a coefficient of 2 before Mg in the reactants. So, this gets us: 2Mg + O2 -> 2MgO.

Key concepts

Combination Reaction

A combination reaction is a type of chemical process where two or more reactants combine to form a single product. This reaction pattern is fundamental in the study of chemistry and showcases the transformative nature of chemicals when they interact. When magnesium metal reacts with oxygen gas, for example, they exhibit a classic combination reaction, forming a composite product – in this case, magnesium oxide. Magnesium and oxygen are different elements that, upon energetic contact, create an entirely new compound. Understanding combination reactions helps us comprehend how more complex substances are formed from simpler ones and is essential knowledge for anyone studying chemistry.

There are various types of combination reactions, but the one we're discussing involves a metal and oxygen, which invariably results in a metal oxide. This is a straightforward type of combination reaction that is often encountered in materials science and metallurgy as well. The applications of understanding such reactions span from building batteries to manufacturing construction materials.

Chemical Reactants and Products

The terms 'reactants' and 'products' are foundational in the field of chemistry, delineating the 'before' and 'after' states in a chemical reaction. Reactants are the starting materials that undergo a change during the reaction, while products are the new substances formed as a result of this change. In our example, magnesium (Mg) and oxygen (O2) are reactants that interact to yield the product magnesium oxide (MgO).

To visualize the transformation clearly, we could think of reactants as ingredients in a recipe and products as the finished dish. It's crucial for students to properly identify reactants and products in a chemical equation to understand the reaction's nature fully. In classroom and laboratory settings, this ability is foundational to predicting the outcomes of reactions and explaining why certain reactants combine to produce specific products. It instills a systematic approach to analyzing and predicting chemical behavior.

Stoichiometry

Stoichiometry is the section of chemistry that deals with the quantitative relationships between reactants and products in a chemical reaction. It involves using balanced equations to determine the relative amounts of substances involved in reactions. The law of conservation of mass is central to stoichiometry, which states that mass is neither created nor destroyed in a chemical reaction. This means all atoms present in the reactants must be accounted for among the products.

To apply stoichiometry to our magnesium and oxygen reaction, we balance the equation so that the number of atoms of each element is the same on both sides of the equation. This balanced equation serves as a recipe that tells us exactly how much of each reactant is needed to produce a certain amount of product. It's like instructions in cooking or baking – to get the expected result, you need the right proportions of ingredients. In stoichiometry, those proportions are given in terms of moles, which measure an amount of substance. Hence, stoichiometry is a vital tool for chemists; it lets them scale reactions up to an industrial level or down to the microscopic level while maintaining precision in the proportions of reactants and products.