2. ab (1) One compound has a black and white sphere, the other compound has one black and two white spheres. Note, there are many other valid answers for this question!

3. Box B System After Reaction (2) Each compound produced has one white and one black sphere, but there is not enough black spheres to react with the last two white spheres

4. (3) “X” is a pure sample of a compound “Y” is a pure sample of an element “Z” is a mixture of two different elements

5. (4a) (4b) (4c) Sample 3 two molecules Only one element is present

6. (5a) (5b) (5c) It’ s pure because every particle is composed of a black and white element. The similar spheres represent fluorine (F 2 ), the different spheres represent HCl “A” represents several of the same compound, “B” is a mixture of different compounds.

7. (6) The diagram represents a solid, and silver is the only solid under these conditions.

8. (7) Each of these are the same compound (one white and one black sphere)

9. (8) Each of these represent a compound, that contains one black and two white elements

10. (9) Notice how the gas has spread out

11. (10) This gas has physically changed to a liquid

12. (11) Carbon monoxide has one carbon (black) and one oxygen (white)

13. (12) black sphere is element “X” white sphere is element “Z”

14. (13a) (13b) (13c) AQ 2 They have covalent bonds as it was stated that the elements were nonmetals Same mass Recall conservation of mass n nrg

15. (14) compound has one white sphere and one black sphere

16. (15) compound is XZ 2

17. (16) element is the double white spheres compound is the black and white sphere

18. (17) double white spheres is one diatomic double black spheres is another diatomic

19. (18) A compound was formed from two different elements. This chemical change produces products that have different chemical properties.