physical and chemical changes

1. The process by which a solid substance changes into a liquid state as a result of heat.
6. A chemical reaction between an acid and a base, resulting in the formation of salt and water.
8. The conversion of a gas or vapor into a liquid state.
10. A chemical reaction involving the gain of electrons or a decrease in oxidation state by a molecule, atom, or ion.
12. The process in which a liquid changes into a solid state due to a decrease in temperature.
13. The formation of a solid from a solution during a chemical reaction.
14. A change in which the substance's form or appearance alters, but its chemical composition remains constant.

2. The chemical reaction between an acid and a base, resulting in the formation of water and a salt.
3. A rapid chemical reaction between a fuel and an oxidant, typically producing heat and light.
4. A chemical reaction between iron and oxygen in the presence of moisture, leading to the formation of iron oxide (rust).
5. The transformation of a liquid into a gas at temperatures below its boiling point.
7. A chemical reaction involving the loss of electrons or an increase in oxidation state by a molecule, atom, or ion.
9. The process in which a gas transforms into a solid without passing through the liquid phase.
11. A process that leads to the formation of new substances with different chemical compositions.
15. The transition of a substance directly from a solid to a gas phase without passing through the intermediate liquid phase.