What is the total number of moles of ions?

Question

in 0.250 L of 0.542 M (NH4)2SO4?

Please explain, thanks

Answer 1

Moles (NH4)2SO4 = 0.250 L x 0.542 M =0.136

(NH4)2SO4 >> 2 NH4+ + SO42-

moles NH4+ = 0.136 x 2 =0.272

moles SO42- = 0.136

total number of moles = 0.272 + 0.136 =0.408

Answer 2

0.250 liters * 0.542 moles/liter = X moles of compound

2 moles of NH4+ / mole of compound * X = C+

1 mole of SO4 / mole of compound * X = A--

total ions = A+ + C--