Question

When balancing a chemical equation, it is usually best to begin with the _______________.

A) simplest molecule

B) most complicated molecule

C) products

D) reactants

Answer 1

To balance a chemical equation, start with the most complicated molecule, use it to balance elements that appear in a single reactant and product, and then progress to simpler molecules, balancing as you go.

Step-by-step explanation:

When balancing a chemical equation, it is usually best to begin with the most complicated molecule. The reason behind this is that the most complicated substance usually has the largest number of different atoms, which provides a good starting point for balancing the overall equation. Here's how you could approach it:

1. Identify the most complex substance, which might be something like Ca3(PO4)2(OH) or C7H16, depending on which reaction you're dealing with.
2. Choose an element(s) that appears in only one reactant and one product, if possible, and adjust the coefficients accordingly.
3. Balance polyatomic ions as a unit if they appear on both sides of the chemical equation.
4. Balance the remaining atoms, ending with the least complex substance. You may use fractional coefficients if necessary and then clear them by multiplying to obtain whole number coefficients.
5. Check to ensure that the numbers of atoms of each element are equal on both sides of the equation.