1. Conservation of Mass

2. Review A physical change does not produce a new substance.
A chemical change does produce a new substance

3. Examples of Physical Changes
Phase changes
Making and separating a mixture
Changing shape

4. Physical Change
In a physical change, no new substance has been created!

5. Ways to recognize Chemical Changes
Gas is released
Release of heat and/or light
Residue (precipitate) forms
Change in colour
Change in temperature

6. Chemical Changes
In a chemical change, a new substance has been produced. In a chemical change, the atoms of the original substances are rearranged, making new substances.

7. Complete page 4 of your workbook

8. Example:
Remember cellular respiration??

9. C O H O

10. C O C O H O

11. Write a word equation for…
Photosynthesis (the process by which plants take in carbon dioxide and water to produce glucose and oxygen).

12. Complete page 5 of your workbook

13. Conservation of Mass The law of conservation of mass states that:
Mass is neither created nor destroyed. It is transformed.
(write that on the top of page 6)

14. Water Hydrogen + Oxygen
Example
Water Hydrogen Oxygen
72 g g ?

15. Water Hydrogen + Oxygen
Example
Water Hydrogen Oxygen
72 g g ?
The mass of the reactants MUST equal the mass of the products.

16. Complete pages 6-7

18. Warmup question…
An engine burns 334 g of diesel and oxygen to produce 1056 g of carbon dioxide and 414 g of water vapour.

19. More atomic history… John Dalton – 1800s Democritus Aristotle
(Indivisible, (Divisible,
Discontinuous) Continuous)
John Dalton – 1800s

20. All matter is made of atoms (indivisible).
More atomic history…
All matter is made of atoms (indivisible).
Atoms of the same element are identical. Atoms of different elements are different !
John Dalton – 1800s

21. Atom, Molecule, Compound, Element?H Xe O O C C H O H H H O C

22. Some basic definitions
Atom:
Molecule:
Element:
Compound:

23. TRUE or FALSE? A compound is always molecule: A molecule is always a compound

24. Complete page 11