Physical Science Crossword Puzzle

2. Characteristics that you can observe or measure without changing the identity of the matter.
5. Chemical reaction where more energy is needed to start the reaction.
10. Mass per unit volume of a substance.
12. Stored energy due to the interactions between particles.
14. A group of atoms that are held together by chemical bonds and act as a unit.
15. Chemical reaction where more energy is released during the reaction.
16. The amount of thermal energy transferred from regions of higher temperature to regions of lower temperatures.
18. Property which occurs when a substance reacts with another substance, changing it into a new substance.
21. Characteristic of matter that can be observed as it changes to a different type of matter.

1. A group of chemical symbols and numbers that represent the element and the number of atoms of each element that makes up a compound.
3. The substance produced by the chemical reaction.
4. Energy in motion.
6. The measure of the average kinetic energy of the particles in a material.
7. The starting substance in a chemical reaction.
8. A substance made of only one type of atom.
9. The ability of a type of matter to burn easily.
11. The amount of space a substance takes up.
13. Matter with a composition that is always the same.
14. The amount of matter in a substance.
17. A small particle that is the building block of matter.
19. Matter changes into other substances with different chemical and physical properties.
20. Type of substance that occurs when atoms of two or more different elements are bonded together.