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

+ WELCOME!1. Grab the materials in your

folder.

2. Take out your homework packet.

+

•No Trash No Detention Bonus

•Homework

•Science Fair

Small Business

+ 80%

+

+

How does a battery work?

+

€

Egg + $1 → Egg -1

+

€

Egg → Egg+1 + $1

+MAD Skillz: Writing electrons in equations

Think of half reactions as money (electrons) in an Easter egg (atom).1) If you gain an electron the money is outside the egg at first,

then goes inside.

2) If you lose an electron, the money is in the egg at first, the goes outside

Write the formula for Mg losing two electrons. 

€

Egg + $1 → Egg -1

€

Egg → Egg+1 + $1

+MAD Skillz: Writing electrons in equations

Think of half reactions as money (electrons) in an Easter egg (atom).1) If you gain an electron the money is outside the egg at first,

then goes inside.

2) If you lose an electron, the money is in the egg at first, the goes outside

Write the formula for Cl gaining an electron

€

Egg + $1 → Egg -1

€

Egg → Egg+1 + $1

+Concentrations

1. If an element gains an electron then it goes through ___________________

2. If an element loses and electron then it goes through ___________________

+Chem-mem-tip

OIL - _________________ _________________ _________________

RIG - _________________ _________________ _________________

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

+Electrical Current

1. To measure electrical current use _______________ (V)

+MAD Skillz: Convert large numbers in scientific notationGoal: Make sure the number of electrons on each side of the equation is balanced.1. If you need to flip an equation, invert the charge (e.g., positive

goes to negative)2. If you need to multiply a side, multiply the entire half reaction

by the number.DO NOT MULTIPLY THE VOLTAGE

3. Cancel out the electrons and drop the remaining elements in the final reaction.

4. Add the final voltage togetherHint: YOU CANNOT HAVE A NEGATIVE VOLTAGE!

Mg2+(aq) + 2e- Cr(s) -2.37V+ Na+(aq) + e- Na(s) -2.71V_______________________________________

+Guided Practice

Clickers

+

What is the correct formatting for Sulfur gaining one electron?

A. S + e- S-

B. S S- + e-

C. S + e- S+

D. S S+ + e-

+

What is the correct formatting for Nitrogen losing two electrons?

A. N +2e- N2-

B. N N2- + 2e-

C. N + 2e- N2+

D. N N2+ + 2e-

+

What is the correct formatting for Iron losing three electrons?

A. Fe +3e- Fe3-

B. Fe Fe3- + 3e-

C. Fe + 3e- FeE+

D. Fe Fe3+ + 3e-

+

What is oxidation?

A. Gain of electrons

B. Loss of electrons

C. Termination of electron

D. A mystical rapper from Nigeria

+

What is the tip to remember what Oxidation and Reduction is?

A. OIL RIG

B. OIG RIL

C. OR IL II

D. OMG

+

Is the following half reaction an oxidation or reduction reaction

A. Oxidation

B. Reduction

+

Why is the following equation an reduction reaction

A. It lost an electron

B. It gained an electron

C. It terminated an electron

D. It changed a proton into an electron

+

Why is the following equation an oxidation reaction

A. It lost an electron

B. It gained an electron

C. It terminated an electron

D. It changed a proton into an electron

Sn(s) Sn2+ + e-

+

Classify the following reaction as either oxidation or reduction. Describe why.

A. Oxidation because it gained an electron

B. Reduction because it gained an electron

C. Oxidation because it lost an electron

D. Reduction because it lost an electron

+

When you add two half reactions to determine voltage, what is your primary goal to solve the problem

A. Have equal number of electrons in the products and reactants

B. Have electrons in the products and reactants

C. Add the equations

D. Add the voltages

+ When adding these two half reactions which equations should be flipped and which should be

multiplied?

A. Flip the bottom and invert the voltage

B. Flip the bottom and keep the voltage the same

C. Flip the top and and invert the voltage

D. 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_______________________________________

+ When adding these two half reactions which equations should be flipped and which should be

multiplied?

A. Flip the bottom and invert the voltage

B. Flip the bottom and keep the voltage the same

C. Flip the top and and invert the voltage

D. 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_______________________________________

+

When adding these two half reactions which equations should be flipped and which should be

multiplied?

A. Flip the bottom and multiply the bottom

B. Flip the bottom and multiply the top

C. Flip the top and multiply the top

D. Flip the top and divide the bottom

Mg2+(aq) + 2e- Cr(s) -2.37V+ Na+(aq) + e- Na(s) -2.71V_______________________________________

+

When adding these two half reactions which equations should be flipped and which should be

multiplied?

A. Flip the bottom and multiply the bottom

B. Flip the bottom and multiply the top

C. Flip the top and multiply the top

D. Flip the top and multiply the bottom

Cu+(aq) + e- Cu(s) 0.52V+ Sn2+(aq) +2e- Sn(s) -0.14V_______________________________________

+

Cu+(aq) + e- Cu(s) 0.52V+ Sn2+(aq) +2e- Sn(s) -0.14V_______________________________________

+

Cr3+(aq) + 3e- Cr(s) -0.74V+ Fe2+(aq) + 2e- Fe(s) -0.44V_______________________________________