Question

Balancing an equation for a reaction ensures that the number of each type of atom is ________on both sides of the equation.

Short answer

Balancing an equation for a reaction ensures that the number of each type of atom is \(equal\) on both sides of the equation.

Step-by-step solution

Understanding Chemical Reactions

In a chemical reaction, the reactants (the substances that are combined) react with each other to form products (the substances that are formed). The conservation of mass states that the total mass of the reactants must be equal to the total mass of the products. This principle applies to the number of atoms of each element in the reactants and products.

Balancing Chemical Equations

A balanced chemical equation shows the conservation of atoms in a chemical reaction. This means that the number of atoms of each element in the reactants (on the left side of the equation) must be equal to the number of atoms of the same element in the products (on the right side of the equation).

Example: Balancing a chemical equation

Consider the following unbalanced chemical equation for the reaction between hydrogen and oxygen to form water: \(H_2 + O_2 → H_2O\) To balance this equation, we need to make sure that the number of hydrogen atoms and the number of oxygen atoms are conserved on both sides of the equation. 1. Count the number of atoms for each element on both sides: Reactants: \(H_2\) contains 2 H atoms, \(O_2\) contains 2 O atoms Products: \(H_2O\) contains 2 H atoms and 1 O atom 2. Find a coefficient (a whole number) that balances the number of atoms for each element: To make the number of oxygen atoms equal on both sides, we can add a coefficient of 2 in front of \(H_2O\) on the product side. 3. Rewrite the balanced equation: \(H_2 + O_2 → 2 H_2O\) Now, there are 2 hydrogen atoms and 2 oxygen atoms on both sides of the equation, so the equation is balanced.

Completing the sentence

From the analysis and example above, we can now complete the sentence: Balancing an equation for a reaction ensures that the number of each type of atom is **equal** on both sides of the equation.

Key concepts

Conservation of Mass

The concept of conservation of mass is fundamental in chemistry and states that mass is neither created nor destroyed in a chemical reaction. This means that the mass of the reactants must equal the mass of the products. When we talk about chemical equations, this means every atom that is present in the reactants must also be accounted for in the products.
In practice, this principle ensures that no matter what transformations happen during a chemical reaction, the total mass remains constant. Thus, when balancing a chemical equation, we are making sure that all elements are accounted for by having the same number of each type of atom on both sides of the equation.

• Mass remains constant: reactant mass = product mass
• Atoms must balance on both sides
• Supports understanding of how substances change and interact

Understanding and applying the conservation of mass is essential for predicting the amounts of products formed in a reaction and ensuring accurate laboratory practices.

Chemical Reactions

A chemical reaction involves the transformation of one or more substances, known as reactants, into new substances referred to as products. This change involves breaking old bonds and forming new ones, which alters the arrangement of atoms. Chemical equations represent these changes and give us a snapshot of how reactants are converted to products.
Chemical reactions are expressed in symbolic form using chemical formulas and symbols. This representation not only shows the substances involved but also helps in visualizing how atoms rearrange during the reaction process. For example, when hydrogen reacts with oxygen to form water, the equation is represented as: \[ H_2 + O_2 \rightarrow H_2O \]

• Reactants undergo transformation
• New products are formed
• Symbols and formulas depict the process

It is crucial to correctly write and balance chemical equations so that they accurately reflect the chemical reaction and comply with the law of conservation of mass.

Atom Conservation

Atom conservation is a vital principle in balancing chemical equations. This concept ensures that the same number of each type of atom is present on both sides of the equation, illustrating that atoms are neither lost nor gained but merely rearranged. This is achieved by adjusting the coefficients in front of the chemical formulas.
Balancing requires careful counting and comparison of the atoms in the reactants and products. For instance, in the reaction between hydrogen and oxygen to create water, the process involves ensuring an equal count, such as balancing the equation from:\[ H_2 + O_2 \rightarrow H_2O \]To:\[ 2H_2 + O_2 \rightarrow 2H_2O \]By doing so, it respects the principle of conservation of atoms, which states:

• Atoms are constant in number before and after the reaction
• Balancing coefficients ensure atom conservation
• Reflects the idea that atoms are simply rearranged

This practice of balancing is critical for any chemist to accurately describe a chemical reaction and its stoichiometry.