Is this a redox reaction? What one is oxidized? reducing?

Question

Cu(OH)2 (s) + 2HNO3 (aq) ---> Cu(NO3)2 (aq) + 2H20 (l)
Fe2O3 (s) + 3CO (g) ---> 2 Fe (s) + 3CO2 (g)
Sr(NO3)2 (aq) + H2SO4 (aq) ----> SrSO4 (s) + 2HNO3(aq)
4Zn(s) + 10H+ (aq) + 2NO3- (aq) ---> 4Zn 2+(aq) + N2O (g) + 5H20 (l)

they can be precipitation or acid base reactions too

Answer 1

In the Copper(II)hydroxide and nitric acid reaction, none of the oxidation numbers of the elements are changing, so it is not a redox reaction.

The Iron(III) oxide and carbon monoxide reaction is a redox. The carbon is being oxidized while the iron is being reduced.

The Strontium nitrate and sulfuric acid reaction is not a redox reaction since none of the oxidation states are changing.

The last one is a redox where the zinc is being oxidized and the nitrogen is being reduced.

Answer 2

Cu(OH)2 + 2HNO3 --> Cu(NO3)2 + 2H2O
Cu(II) goes to Cu(II); no oxidation/reduction
You should be able to see that this is an acid/base reaction-
MOH + HA --> MA + H2O

Fe(III) to Fe (reduced); C(II) to C(IV) (oxidized)

Look for oxidation number changes; none in the 3rd equation, but (s) tells you a precipitate formed from the (aq) reactants.

Zn to Zn(II) an obvious oxidation; what is reduced?