Synthesis reaction — Science definition
Defined in 2 courses:
- A reaction that combines smaller molecules into a larger one — a building-up reaction. (Life Science: Biology)
- A reaction where two or more simpler substances combine to form a single, more complex product (A + B → AB). (Physical Science: Chemistry)
Where it is taught
- Biochemical Reactions & Energy — Investigating the Chemistry of Life, Life Science: Biology, Grade 10
- Types of Reactions — Reactions, Moles & Composition, Physical Science: Chemistry, Grade 11
In use
The first family is the synthesis reaction, sometimes called a combination reaction, where two or more simpler substances join into a single, more complex product.
Types of Reactions
Questions using synthesis reaction
Problem 1
Explain how a decomposition reaction and a synthesis reaction can be linked together by ATP inside a cell.
Answer and explanation
Energy-releasing metabolism supports ATP production. ATP hydrolysis coupled to synthesis or transport can make the combined process favorable. No energy is created, and the full reactions, not bond breaking alone, determine the balance.
Problem 2
Which of these is a synthesis reaction?
- 2H₂ + O₂ → 2H₂O
- CaCO₃ → CaO + CO₂
- Zn + 2HCl → ZnCl₂ + H₂
- CH₄ + 2O₂ → CO₂ + 2H₂O
Answer and explanation
2H₂ + O₂ → 2H₂O
Two elements combining into a single compound (A + B → AB) is synthesis.
Taught alongside
- chemical reaction
- reactant
- product
- decomposition reaction
- ATP
- metabolism
- single-replacement reaction
- double-replacement reaction
- combustion reaction
- activity series