1. Chemistry is a material science! Define Chemistry

2. Chemistry is the study of matter: its composition, the changes matter undergoes, and the energy associated with these changes. Definition

3. Matter is anything that has mass and takes up space, or has volume. Matter Defined

4. This fundamental definition of matter leads to a common property of matter, namely, density. Density is equal to the mass divided by the volume. Density: a spin-off

5. The “makeup” of matter is its composition. This answers the question what kind of atoms and molecules are present in this matter. Composition

6. Matter composed of only one kind of particle such as an atom or molecule is a pure substance or simply a substance. Substances

7. Substances are made of only one kind of element or compound.

8. Substances have physical properties such as melting and boiling temperature, solubility and density. Physical Properties

9. Physical properties can be observed without changing the composition of matter. For example, copper wire can conduct electricity and remain copper.

10. Chemical properties deals with how a substance will react with another substance.

11. Neon gas is non reactive with all substances. Sodium metal is highly reactive and must kept under oil to prevent reaction with air or water.

12. The chemical property of a substance is basically its reactivity.

13. Physical properties that are the same regardless of the sample size are called intensive properties.

14. Intensive properties such as density and melting temperature can be used to identify the substance.

15. Extensive properties such as mass or volume will vary with the sample size.

16. Elements are composed of the same type of atom (same element e.g. Ne) or molecules of the same type of atom (element e.g. N 2 ).

17. Compounds are composed of atoms of different elements in definite ratios. Carbon dioxide is CO 2 and carbon monoxide is CO.

18. Mixtures are a combination of An element with element or Element with a compound or Compound with other compounds

19. Mixtures are a combination of substances with variable mass ratios.

20. Changes in matter can be classified as a physical change, a chemical change or a nuclear change.

21. Substances undergoing a physical change may have an alternate state of matter or change in shape, but never change in composition of the substance itself.

22. When H 2 O(l) as a liquid freezes it is H 2 O(s) as a solid, but there is no change is the fixed ratio of H:O in H 2 O. Thereby there is not change in the composition.

23. Chemical changes are called chemical reactions and are more difficult to reverse than physical changes.

24. In a chemical reaction new substances (called products) are formed with a new and different set of physical and chemical properties.

25. For example, when H 2 and O 2 react to form H 2 O. The H 2 O that extinguishes flames was produced from O 2 that supports combustion and H 2 that is highly flammable

26. Likewise the freezing and boiling temperature of both H 2 and O 2 is much lower than the corresponding freezing and boiling temperature of H 2 O.

27. A nuclear change releases the most of energy of all the changes. In nuclear reactions atoms of one element are often changed into atoms of different element.

28. Energy associated with changes. Type of change in matter Change in Energy Physical Change H 2 O(s)  H 2 O(l) 334 joules needed endothermic Chemical Change 2H 2 (g) +O 2 (g)  2H 2 O(l) 285.8 kJ exothermic Nuclear Fusion 3 H + 2 H  4 He + 1 n 1.7 x 10 9 kJ exothermic