Why can't you balance by changing H2O to H4O2?
Water is H2O, not H4O2. Learn how coefficients balance an equation without inventing new molecules.
Try this lessonFind the step that makes it click.
Pick a topic in math, science, chemistry, or writing. Try an example, get a clue, and practise at your pace.
No account or card needed. Practice answers stay on this page and aren’t saved.
1 lesson for “Balancing chemical equations”
Also close
What is the opposite of adding 7?
Owen solved x + 7 = 12 by computing 12 + 7 = 19. He added again instead of undoing the addition.
Try this lessonWhy can't I just move the x?
Milo solved 3x + 2 = x + 10 by adding x to both sides: 4x = 12, so x = 3. Substitution showed 11 does not equal 13.
Try this lessonHow does subtracting the equations remove a variable?
When both equations share a term like 2y, that term becomes your exit: subtract the equations and it disappears.
Try this lessonSynthesis or combustion: how can you tell?
A reaction can be named by its pattern, not its colors or smells. Look at how many substances come in and how many go out.
Try this lessonHow does y = 2x + 1 help you solve x + y = 10?
Two equations with two unknowns feel harder than one. Substitution turns the pair into a single equation with one letter.
Try this lessonWhere did the negative sign go?
A negative sign belongs to the number next to it. Keeping that number together can prevent an almost-correct equation from turning into the wrong answer.
Try this lessonTry a step. See what clicks.
Work through an example, ask for a clue when you need one, then try a new question on your own.
Browse by subject
All of math, science, chemistry and writing lessons or search across the whole library above.
Learn by trying
Fill in one step at a time and check your answer. Need help? Tap “Give me a clue.”
Treat these examples as a starting point for a conversation, not as a replacement for your teacher’s guidance.
Need help with your own question? See how the family service works