Question

which of the following is a chemical change? melting butter igniting a gas fire condensation forming on a window ice cracking a milk bottle

Explanation:

A chemical change results in the formation of new substances. Melting butter is a physical change (change of state). Condensation is also a physical change (gas to liquid). Ice cracking a milk - bottle is a physical change due to expansion. Igniting a gas fire involves a chemical reaction between the gas and oxygen to produce heat, light and new substances like carbon - dioxide and water vapour.

Answer:

igniting a gas fire