by dreyden del rio
physical and chemical properties
Chemical property: is a property or behavior of a substance when it undergoes a chemical change or reaction
Chemical properties of a substance can include toxicity, oxidation, and flammability. Iron oxidizes and becomes rust.
The measurement of a physical property may change the arrangement of matter in a sample, but not the structure of its molecules. In other words, a physical property may involve a physical change, but not a chemical change.
Examples include mass, density, color, boiling point, temperature, and volume.
Chemical changes take place on the molecular level. A chemical change produces a new substance.
Examples of chemical changes include combustion (burning), cooking an egg, rusting of an iron pan, and mixing hydrochloric acid and sodium hydroxide to make salt and water.
Physical changes are concerned with energy and states of matter. A physical change does not produce a new substance. Changes in state or phase (melting, freezing, vaporization, condensation, sublimation) are physical changes.
Examples of physical changes include crushing a can, melting an ice cube, and breaking a bottle.
A chemical reaction is a process that is usually characterized by a chemical change in which the starting materials (reactants) are different from the products. Chemical reactions tend to involve the motion of electrons, leading to the formation and breaking of chemical bonds. There are several different types of chemical reactions and more than one way of classifying them.