Question

Which of the following equations shows a chemical change?
Responses
1) C3H8+5O2→3CO2+4H2O
2) H2O(s)→H2O(g)
3) NH3(g)→NH3(l)
4) C2H5OH(l)→C2H5OH(g)

Answer 1

The equation that shows a chemical change is:

**1) C3H8 + 5O2 → 3CO2 + 4H2O**

This equation represents the combustion of propane (C3H8) in the presence of oxygen (O2), resulting in the formation of carbon dioxide (CO2) and water (H2O), indicating a chemical transformation of the reactants into different products.

The other equations represent physical changes:

2) H2O(s) → H2O(g) (melting and boiling of water)
3) NH3(g) → NH3(l) (condensation of ammonia)
4) C2H5OH(l) → C2H5OH(g) (evaporation of ethanol)