Lesson 2 of 13
From words to formulae
Show on a big screenCharcoal burns in a stove. Carbon and oxygen become carbon dioxide.
Step 1 of 3
- Word sentence: hydrogen and oxygen give water.
- Swap each name for its formula: H₂, O₂, H₂O.
- Skeleton equation: H₂ + O₂ → H₂O.
Tap the pieces in order to build each formula sentence.
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The rule
A word equation names reactants and products in words. A skeleton equation writes the same names as formulae. The arrow means gives.
Reactants go on the left of the arrow. Products go on the right.
| Word equation | Skeleton equation |
|---|---|
| carbon and oxygen give carbon dioxide | C + O₂ → CO₂ |
| iron and sulphur give iron sulphide | Fe + S → FeS |
| hydrogen and chlorine give hydrogen chloride | H₂ + Cl₂ → HCl |
A state symbol can follow a formula. (s) is solid, (l) liquid, (g) gas, (aq) dissolved in water. Example: C(s) + O₂(g) → CO₂(g).
A skeleton equation just replaces each name with its formula. It may not carry the right count of every atom. Checking the count is a separate step.
Try the lab to finish this lesson.