Question

Identify the reaction type shown and describe the clues that were used to identify it.

Fe2O3 + 2SiO2 → Fe2Si2O7

Answer 1

This is a combination (synthesis) reaction and, more specifically, an acid–base reaction between oxides (a metal‑oxide + acidic nonmetal oxide → a salt). It can also be seen as a solid‑state high‑temperature formation of an iron silicate (iron(III) pyrosilicate, Fe2Si2O7).

Clues used to identify it:
- Only one product is formed from two simpler reactants → characteristic of a synthesis/combination reaction.
- Reactants are Fe2O3 (a basic metal oxide) and SiO2 (an acidic nonmetal oxide). Basic oxide + acidic oxide commonly give a salt (here a silicate), so it is an oxide acid–base reaction.
- Oxidation states do not change (Fe remains +3, Si +4) → not a redox reaction.
- Stoichiometry balances (Fe:2, Si:2, O:7), consistent with formation of a single silicate product.
- Context: such reactions typically occur in the solid state at elevated temperature to form mineral/ceramic silicates.