1 Calcium ion / formula unit times 0.5 moles CaCl2 x 6.02 x 10^23 =
<span>3.01 x 10^23 Calcium ions.</span>
19 has 2 factors (1,19)
21 has 4 factors (1,3,7,21)
23 has 2 factors (1,23)
25 has 3 factors (1,5,25)
you need the nearest number 25 that has 5 factors or more :28(1,2,4,7,14,28)
