Wednesday

February 10, 2016
Posted by **Alex** on Sunday, February 10, 2008 at 8:20pm.

Write an label the oxidation and reduction half-reaction equations.

a) Ni(s) + Cu(NO3)2(aq) -> Cu(s)+ Ni(No3)2(aq)

oxidation - Ni(s) -> Ni2+(aq) + 2e-

reduction - Cu2+(aq) + 2e- -> Cu(s)

b) Pb(s) + Cu(NO3)2(aq) -> Cu(s) + Pb(NO3)2(aq)

oxidation - Pb(s) -> Pb2+(aq) + 2e-

reduction - Cu2+(aq) +2e -> Cu(s)

c) Ca(s) + 2HNO3(aq) -> H2(g) + Ca(NO3)2(aq)

oxidation - Ca(s) -> Ca2+(aq) + 2e-

reduction - 2H+(aq) + 2e- -> H2(g)

d) 2Al(g)+ Fe2O3(s) -> 2Fe(l) + Al2O3(s)

oxidation - 2Al ->

I have no idea what to do with the last one. If I made any mistakes or did anything wrong can someone correct them.

Oxidation Numbers

Assign oxidation numbers to chloride in each of the follow chemicals.

HCl = +1?

Cl2 = 0?

NaClO = ?

Cl- = -1?

HClO3 = either +1 or -3?

ClO3- = -3?

KClO2 - +2?

ClO2 = +2?

HClO4 = +4?

I have no idea if I'm doing these right. Can someone explain oxidation numbers and correct those?

Also can someone do an example in this and explain how they got it. I don't understand the concept.

Assign oxidation numbers to manganese in each of the following chemicals.

MnO4^2-(aq)

Use oxidation numbers to identify the oxidation and reduction atoms

MnO4-(aq) + H2Se(g) + H+(aq) -> Se(s) + Mn2+(aq) + H2O(l)

Can someone please do those examples and explain how they got the answers because I don't understand oxidation numbers.

- Chemistry -
**DrBob222**, Sunday, February 10, 2008 at 8:48pm**The first three equations are ok.**

d) 2Al(g)+ Fe2O3(s) -> 2Fe(l) + Al2O3(s)

oxidation - 2Al ->

**Al goes from 0 oxidation state on the left to zero on the right so it is oxidized. Fe goes from +3 on the left to 0 on the right so it is reduced. I assume you can write the half equations.**

have no idea what to do with the last one. If I made any mistakes or did anything wrong can someone correct them.

Oxidation Numbers

Assign oxidation numbers to chloride in each of the follow chemicals.

HCl = +1?**No, H is +1 so Cl is -1**

Cl2 = 0?**right**

NaClO = ?**Na is +1, O is -2; therefore, Cl is what to make NaClO zero. Cl must be +1.**

Cl- = -1?**right**

HClO3 = either +1 or -3?**H is +1, O is -2, there are 3 of them to make total on O of -6; therefore, what must Cl be to have HClO3 zero. Cl must be +5**

ClO3- = -3? +5. O is -6 and Cl must be +5 to leave a -1 charge on the ion.

KClO2 - +2?**K is +1, O is -4, therefore, Cl must be +3**

ClO2 = +2?**Cl must be +4 to zero out the -4 from O2**

HClO4 = +4? H is +1, O is -8; therefore, Cl must be +7

I have no idea if I'm doing these right. Can someone explain oxidation numbers and correct those?

Also can someone do an example in this and explain how they got it. I don't understand the concept.

Assign oxidation numbers to manganese in each of the following chemicals.

MnO4^2-(aq)**O is -8 so Mn must be +7 to leave a -1 charge on the ion.**

Use oxidation numbers to identify the oxidation and reduction atoms

MnO4-(aq) + H2Se(g) + H+(aq) -> Se(s) + Mn2+(aq) + H2O(l)

**Mn goes from +7 on the left to +2 on the right. Se goes from -2 on the left to 0 on the right.**

Can someone please do those examples and explain how they got the answers because I don't understand oxidation numbers.

**I think you have guessed at some of the answers and we don't want to do that, do we?. I think I have a good site with minimal rules that can clear this up for you if you want it. I hope I turned off the bold for your work and used bold for mine. If I didn't I assume you will know what you typed and what I typed, bold or not**

- Chemistry -
**DrBob222**, Sunday, February 10, 2008 at 8:54pmMinimal but simple rules to live by for redox. Oxidation numbers are nothing more than a book keeping method.

http://dbhs.wvusd.k12.ca.us/webdocs/Redox/Meaning-of-Redox.html

(Broken Link Removed)

- Chemistry -