calculate number of ions in 100ml .1M copper nitrate solution?

Answer 1

Moles of Copper nitrate = 100 x 0.1 /1000 = 0.01

If the formula is CuNO3 >> Cu+ + NO3- ( Copper (I) nitrate )
Total moles = 2 x 0.01 = 0.02
1 mole ==> 6.02 x 10^23
Number of ions = 0.02 x 6.02 x 10^23 = 1.2 x 10^22

If the formula is Cu(NO3)2 >> Cu2+ + 2 NO3- ( Copper (II) nitrate )
total moles = 3 x 0.01 = 0.03
number of ions = 0.03 x 6.02 x 10^23 =1.8 x 10^23

Answer 2

Here are the concepts.

First calculate the moles of the compound. You have 0.1 Liter of 0.1 M. Sounds like approx. .01 moles of compound.

We need to know whether it is Copper I or Copper II. Assuming it is Copper II, thee will be 3 moles of ions for each mole of compound. So your answer will be the above, times 3.