Chem Unit 2 (Redox Reactions) Flashcards Preview

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Flashcards in Chem Unit 2 (Redox Reactions) Deck (11)
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1
Q

Sum on both sides must be…

A

… equal!

2
Q

Oxidising agents…

A

gain electrons

so are themselves reduced

3
Q

Reducing agents

A

lose electrons

so are themselves oxidised

4
Q

What are the rules for half-equations?

A

1) Work out oxidation states
2) Work out what is oxidising agent and therefore reducing agent.
3) Balance any elements that aren’t O or H
4) Add H20’s for oxygen-deficient side and add H+ for hydrogen-deficient side.
5) Check charges and add correct number of electrons to oxidising side (side that has gained electrons)

5
Q

oxygen never changes…

A

….from 2- so all the other elements are the ones that change and become reducing or oxidising agents

6
Q

2OH- means that…

A

…. it’s 2- for that molecule so you have to times the balanced equation by the overall charge

7
Q

What is the rule about the added electrons?

A

added electrons always go on the oxidising agent (that has gained electrons)

8
Q

What do you do if there is a small number next to the oxidising or reducing agent next to oxygen (e.g. Cr2 07)

A

You divide by that small number once you have worked out the oxidation number the element should have.

9
Q

4H+ ion instead of 2H+ ions means?

A

It adds a +4 charge instead of a 2+ charge to whatever side it is on.

10
Q

0 is always 2- except for in peroxides when its -1 and flurodes when its.? 0F2

A

2+

11
Q

Hydroghen is always 1+ except for in metal hydrides like calcium hydride, magnesium hydride when its..? H202

A

1-

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