Count atoms and molecules in chemical reactions

Concept

**What you'll learn** This lesson covers **Count atoms and molecules in chemical reactions**. Understanding this topic builds your mathematical foundation and connects to other ideas in the course. **Key ideas** Work through the definitions, examples, and procedures. Pay attention to when and how to apply the main concept. Practice with the exercise below to reinforce your understanding. **Why it matters** These skills appear in later lessons and in real-world applications. Take time to check your work and use the quiz to confirm you've got the main idea.

Try it

Practice: Count atoms and molecules in chemical reactions. 1. Work through one example from the concept section. 2. Try a similar problem with different numbers or a slight variation. 3. Explain in one sentence how you knew what to do.

Concept Check

Key terms

Balance the Equation

Edit the coefficients (numbers in front of each formula) so the number of atoms of each element is the same on both sides.