WELCOME! 1. Grab the materials in your folder . 2. Take out your homework packet .

1. WELCOME! 1. Grab the materials in your folder. 2. Take out your homework packet.

2. Small Business • No Trash No Detention Bonus • Homework • Science Fair

3. 80%

5. How does a battery work?

8. MAD Skillz: Writing electrons in equations • Think of half reactions as money (electrons) in an Easter egg (atom). • If you gain an electron the money is outside the egg at first, then goes inside. • If you lose an electron, the money is in the egg at first, the goes outside Write the formula for Mg losing two electrons.

9. MAD Skillz: Writing electrons in equations • Think of half reactions as money (electrons) in an Easter egg (atom). • If you gain an electron the money is outside the egg at first, then goes inside. • If you lose an electron, the money is in the egg at first, the goes outside Write the formula for Cl gaining an electron

10. Concentrations • If an element gains an electron then it goes through ___________________ • If an element loses and electron then it goes through ___________________

11. Chem-mem-tip OIL - _________________ _________________ _________________ RIG - _________________ _________________ _________________

12. Classify the following reaction as either an oxidation or reduction half reaction.

13. Electrical Current • To measure electrical current use _______________ (V)

14. MAD Skillz: Convert large numbers in scientific notation • Goal: Make sure the number of electrons on each side of the equation is balanced. • If you need to flip an equation, invert the charge (e.g., positive goes to negative) • If you need to multiply a side, multiply the entire half reaction by the number. • DO NOT MULTIPLY THE VOLTAGE • Cancel out the electrons and drop the remaining elements in the final reaction. • Add the final voltage together • Hint: YOU CANNOT HAVE A NEGATIVE VOLTAGE! Mg2+(aq) + 2e- Cr(s) -2.37V + Na+(aq) + e- Na(s) -2.71V _______________________________________

15. Guided Practice Clickers

16. What is the correct formatting for Sulfur gaining one electron? • S + e-  S- • S  S- + e- • S + e-  S+ • S  S+ + e-

17. What is the correct formatting for Nitrogen losing two electrons? • N +2e-  N2- • N  N2- +2e- • N + 2e-  N2+ • N  N2+ + 2e-

18. What is the correct formatting for Iron losing three electrons? • Fe +3e-  Fe3- • Fe  Fe3- +3e- • Fe + 3e- FeE+ • Fe  Fe3+ + 3e-

19. What is oxidation? • Gain of electrons • Loss of electrons • Termination of electron • A mystical rapper from Nigeria

20. What is the tip to remember what Oxidation and Reduction is? • OIL RIG • OIG RIL • OR IL II • OMG

21. Is the following half reaction an oxidation or reduction reaction • Oxidation • Reduction

22. Why is the following equation an reduction reaction • It lost an electron • It gained an electron • It terminated an electron • It changed a proton into an electron

23. Why is the following equation an oxidation reaction • It lost an electron • It gained an electron • It terminated an electron • It changed a proton into an electron Sn(s)  Sn2+ + e-

24. Classify the following reaction as either oxidation or reduction. Describe why. • Oxidation because it gained an electron • Reduction because it gained an electron • Oxidation because it lost an electron • Reduction because it lost an electron

25. When you add two half reactions to determine voltage, what is your primary goal to solve the problem • Have equal number of electrons in the products and reactants • Have electrons in the products and reactants • Add the equations • Add the voltages

26. When adding these two half reactions which equations should be flipped and which should be multiplied? • Flip the bottom and invert the voltage • Flip the bottom and keep the voltage the same • Flip the top and and invert the voltage • Flip the top or bottom as long as the voltage also flips • Sn2+(aq) + 2e- -> Sn(s) -0.14V • + Mn2+(aq) + 2e- -> Mn(s) -1.18V _______________________________________

27. When adding these two half reactions which equations should be flipped and which should be multiplied? • Flip the bottom and invert the voltage • Flip the bottom and keep the voltage the same • Flip the top and and invert the voltage • Flip the top or bottom as long as the voltage also flips • Ti+(aq) + e- -> Ti(s) -0.34V • + Rb+(aq) + e- -> Rb(s) -2.92V • _______________________________________

28. When adding these two half reactions which equations should be flipped and which should be multiplied? • Flip the bottom and multiply the bottom • Flip the bottom and multiply the top • Flip the top and multiply the top • Flip the top and divide the bottom Mg2+(aq) + 2e- Cr(s) -2.37V + Na+(aq) + e- Na(s) -2.71V _______________________________________

29. When adding these two half reactions which equations should be flipped and which should be multiplied? • Flip the bottom and multiply the bottom • Flip the bottom and multiply the top • Flip the top and multiply the top • Flip the top and multiply the bottom Cu+(aq) +e- Cu(s) 0.52V + Sn2+(aq) +2e- Sn(s) -0.14V _______________________________________

30. Cu+(aq) +e- Cu(s) 0.52V + Sn2+(aq) +2e- Sn(s) -0.14V _______________________________________

31. Cr3+(aq) + 3e- Cr(s) -0.74V + Fe2+(aq) + 2e- Fe(s) -0.44V _______________________________________