Oxidation-Reduction Reactions 2

Oxidation Numbers

100

What is the oxidation number of oxygen usually?

-2

200

What is the oxidation number of a monatomic ion?

Its charge

300

What are the oxidation numbers of the elements in KCl?

K = +1, Cl = –1

400

What are the oxidation numbers of the elements in the compound H₃PO₄?

H = +1, and O is almost always -2
so 3(1) + P + 4(-2) = 0  
P -5 = 0   -> P = 5

H = +1, P = +5, O = –2

500

What are the oxidation numbers of the elements in the ion SO₃^2–?

S + 3(-2) = -2
S -6 = -2  --> S = +4

S = +4, O = –2

Vocabulary

100

What is oxidation?

A reaction in which the atoms or ions of an element experience an increase in their oxidation number, meaning LEO -> Losing electrons is oxidation.

200

Reaction in which the oxidation state of an element decreases, or it gains electrons.

What is Reduction?

300

A substance that has the potential to cause another substance to be reduced?

What is Reducing Agent?

400

A number assigned to an atom in a molecular compound or ion that indicates the general distribution of electrons among the bonded atoms.

What is oxidation state?

500

Any chemical process in which elements undergo changes in oxidation number.

What is Oxidation- Reduction Reaction?

Oxidation- Reduction

100

What is oxidized?      

F₂ + Mg  -->  2F^– + Mg²⁺

Mg

200

Oxidation half reaction in 

3Cu + 2NO₃  --> 3Cu²⁺ + 2NO 

and 

What is the Reduction half-reaction?

Oxidation:     What is 3Cu --> 3Cu²⁺ 

and 

Reduction:      2NO₃  --> 2NO

300

Reducing agent in H₂  +  Cl₂  -->  2HCl

What is H?  (What's being oxidized is the reducing agent.)

400

What is decrease their oxidation number?

Oxidizing agent  or  Reducing agent?

In order to have their oxidationnumber go down they have to gain electrons, so they are being reduced (GER), so they must be the Oxidizing agent.

500

How does the number of electrons lost in the oxidation half-reaction compare with the number gained in the simultaneous reduction half-reaction?

The two numbers are always equal.  That's how you balance a Redox reaction.

Balancing RedoxReactions

100

After balancing the redox equation
FeCl₃ + Zn --> ZnCl₂ + Fe, 

the coefficients, in order from left to right, are

What is 2, 3, 3, 2?

200

The redox equation 

H₂ + S + 2O₂ --> 2H⁺ + SO₄^2– is

What is correctly balanced?

300

After balancing the redox equation
Bi(OH)₃ + SnO₂²  --> Bi + SnO₃^2– + H₂O,

the coefficients, in order from left to right, are

What is 2, 3, 2, 3, 3?

400

After balancing the redox equation
Cr₂O₇^2– + SO₂ + H⁺  -->  Cr³⁺  +  HSO₄^– + H₂O, 

the coefficients, in order from left to right, are

What is 1, 3, 5, 2, 3, 1?

500

Write the oxidation half-reaction and then the reduction half-reaction, balancing elements, except H or O.

Mn²⁺  +  BiO₃^-  -->  Bi³⁺  +  MnO₄^-

Oxidation:  Mn²⁺  -->  MnO4- 

Reduction:  BiO₃^-  -->  Bi³⁺

Random Stuff

100

Why didn't the dog want to play football?

Because it was a boxer?

200

What is the Braves record so far this season?

Who is 17-8 ?

300

Room number of Mrs. Bragg's class

352

400

Choose:

A) How do you shoot a red elephant?

B) How do you shoot a green elephant?

A) If you said, "with a blue elephant gun," or "with a red elephant gun" -100

"Paint it blue, then shoot it with a blue elephant gun."

B) If you said, "with a green elephant gun," or -100

Answer:  "Hold its trunk until it turns red, then paint it blue, then shoot it with a blue elephant gun." +100

500

You have 10 fish, 5 drown, 3 come back to life. How many fish do you have?

Huh?!  Fish can't drown!