2. Chemistry II Test Review

3. color change: fire burns wood to black ashes temperature change: a chemical ice pack cools down when “cracked.” gas released: smoke from a fire precipitate: two clear liquids are combined to and a white solid appears new properties: poisonous chlorine gas when mixed with sodium, becomes edible salt. 1) What are the five “evidences of a chemical reaction? Give an example of each.

4. a precipitate is a solid formed when two liquids are reacted together. 2) What is a precipitate?

5. Law of Conservation of Mass: Matter is neither created or destroyed in a chemical reaction, it means the total mass of the products will be the same as the total mass of the reactants. 3) What is the Law of Conservation of Mass? Explain what it means in a chemical reaction.

6. A) 1 B) 1 C) 1 D) 3 4) How many molecules are of each one is shown? Use the following compounds to answer #4-6 a) FePO 4 b) NH 4 NO 3 c) Mn(NO 3 ) 3 d) 3H 2 O

7. A) 3 B) 3 C) 3 D) 2 5) How many elements in each one is shown? Use the following compounds to answer #4-6 a) FePO 4 b) NH 4 NO 3 c) Mn(NO 3 ) 3 d) 3H 2 O

8. A) 6 B) 9 C) 13 D) 9 6) How many atoms in each one is shown? Use the following compounds to answer #4-6 a) FePO 4 b) NH 4 NO 3 c) Mn(NO 3 ) 3 d) 3H 2 O

9. Which of the equations below are balanced? H 2 (gas) + O 2 (gas)  H 2 0 (liquid) 2H 2 (gas) + O 2 (gas)  H 2 0 (liquid) 2H 2 (gas) + O 2 (gas)  2H 2 0 (liquid) 2H 2 (gas) + 2O 2 (gas)  H 2 0 (liquid) 7)

10. 2H 2 (gas) + O 2 (gas)  2H 2 0 (liquid) Copy the balanced equation from #7 and label the products, coefficients, and reactants. 8) reactants products coefficients subscripts

11. 2H 2 (gas) + O 2 (gas)  2H 2 0 (liquid) Extra discussion: A) How many molecules of each one is shown. 2 H 2 molecules and 2 H 2 O molecules B) How many elements in each one is shown reactant = two elements -Hydrogen and oxygen product = two elements -Hydrogen and oxygen C) How many atoms in each one is shown? reactant = 4 Hydrogen and 2 oxygen product = 4 Hydrogen and 2 oxygen Copy the balanced equation from #7 and label the products, coefficients, and reactants. 8)

12. What are valence electrons? What do they help to determine about an element? Valence electrons are the electrons on the outer energy level of an atom. They determine the atoms reactivity. They are highlighted in yellow below! 10) p=17 n =18

13. 1 23 4 5 6 7 8 Valence electrons are in a pattern on the periodic table as shown below in red. 10) Continued

14. Give the number of protons, neutrons and electrons for the element chlorine. (hint: APE MAN). 11) A tomic # - 17Chlorine P rotons - 17 E lectrons - 17 M ass - 35 A tomic # - 17 N eutrons - 18

15. Draw a Bohr Model of Boron. Be sure to show the protons, neutrons and electrons. 12) p=17 n =18 A tomic # - 17Chlorine P rotons - 17 E lectrons - 17 M ass - 35 A tomic # - 17 N eutrons - 18

16. Sketch a periodic table. Label wher the metals, non- metals, metalloids are located. List at least one property of each. Label the Nobel Gasses. Metal: Shiny, malleable, ductile, good conductor Non-metal: dull, brittle, not malleable or ductile or conductor 13) metals Non-metals metalloids Noble Gasses

17. What is a subscript 15) Subscript: A subscript is the “small number” that shows how many of a particular element is in a compound. 3H 2 0 The little two in H 2 0 tells us there are two hydrogen atoms in each water molecule

18. What is a coefficient 16) Coefficient: A coefficient is the “big number” that shows how many of the compound is being used. 3H 2 0 The big three in front of the H 2 0 tells us there are three water molecules (compounds).

19. Describe phase changes. Is it a chemical or physical change? 17) phase change: A TYPE OF PHYSICAL CHANGE - moving from one state of matter to another: Examples melting: solid  liquid boiling: liquid  gas condensing: gas  liquid freezing: liquid  solid

20. What do elements in the same group have in common? (vertical or horizontal) Elements in the same group share similar properties because they have the same number of valence electrons. They are the columns (vertical) on the periodic table. Groups / families 18)

21. What do elements in the same period have in common? (vertical or horizontal) Elements in the same period have the same number of energy levels (rings). They are the rows (vertical) on the periodic table. periods 19)

22. Becoming more reactive! Becoming more reactive Describe the reactivity of elements on the periodic table as you move away from the stair step line. What groups are most reactive? Least Reactive? Elements are more reactive the further away from the stair step line you move. The exception to this is the Noble Gasses (column 18) which isn’t reactive at all!. 20) Not reactive at all!

23. extra slides from old reviews

24. Sketch a periodic table. Draw an arrow to show how you would find elements with similar properties. Elements with similar properties are found in the same group or family They are the columns on the periodic table Groups / families 15)

25. What is “APE MAN” and what does it mean? 16) A P E M A N tomic number rotons lectrons ass number tomic number eutrons All equal A subtraction problem

26. Compare a chemical change to a physical change (be sure and define them) and give an example of each. 17) Chemical Change: a change that produces a new substance (it can not be changed back without a chemical reaction. Example: burning a stick. Physical Change: a change that changes the physical properties of the substance, but doesn’t change what it is. Example: tearing paper

27. 2H 2 (gas) + O 2 (gas)  2H 2 0 (liquid) 8) Write the balanced equation for number 7 in words. two hydrogen molecules plus one oxygen molecule yields (or produces) two water molecules

28. Draw a dot diagram of Sodium. Use the dot diagram to explain why it loses electrons. Sodium is a metal and likes to lose an electron. It is easier to lose one electron to become more stable than gain 7 electrons. 10) Na

29. Draw a dot diagram of chlorine. Use the dot diagram to explain why it gains electrons. Chlorine is a nonmetal and likes to gain an electron. It is easier to gain one electron to become more stable than lose 7 electrons. 11) Cl

30. Based on #10 & 11, what type of elements gain electrons? Which ones lose electrons? Metals (on the left) have fewer electrons in their outer ring, so they are electron losers (donors). Non-Metals (on the right) have nearly full outer rings, so they tend to grab or gain electrons. 12)

31. electron losers electron gainers 12) continued