This document provides definitions and examples for various chemistry concepts. It defines matter as anything that has mass and volume, and gives a cell phone as an example. Not matter is defined as things without mass or volume, such as music. Pure substances consist of only one type of particle, like aluminum foil. Elements cannot be separated further, like gold. Compounds are composed of two or more elements with constant composition, such as table salt. Mixtures contain substances not chemically combined, such as Coke. Physical changes alter form or state but not substance, while chemical changes produce new substances, like paper ashes or popcorn.

1. Real Life Chemistry By : Jake Han

19. Chemical change 2 - Popcorn is another example of chemical change because like the first example, it cannot be brought back to their original forms after putting into the microwave oven.