The best way to approach such a question is by checking the solubility rules for each of the ionic compounds (more here: http://www.chem.sc.edu/faculty/morgan/resources/solubility/).
Let's start with Co(NO3)2. According to the aforementioned solubility rules, all nitrate (NO−3) salts are soluble, so we would get
Co(NO3)2(aq)→Co2+(aq)+2NO−3(aq)
This means that the concentrations of Co2+ and NO−3 will be
0.50molesCo(NO3)21Lsolution⋅1moleCo2+1moleCo(NO3)2=0.50M Co2+
0.50molesCo(NO3)21Lsolution⋅2molesNO−31moleCo(NO3)2=1.0M NO−3
Notice that the NO−3's concentration will be twice as big as the concentration of Co(NO3)2, since 2 moles of the former are produced for every 1 mole of the latter.
Moving on to Fe(ClO4)3. The solubility rules tell us that all perchlorate (ClO−4) salts are soluble, so we will get
Fe(ClO4)3(aq)→Fe3+(aq)+3ClO−4(aq)
Therefore, the concentrations of the two ions will be
1moleFe(ClO4)31Lsolution⋅1moleFe3+1moleFe(ClO4)3=1M Fe3+
1moleFe(ClO4)31Lsolution⋅3molesClO−41moleFe(ClO4)3=3M ClO−4