The answer is 0.0245 moles
(1) Find the molar mass of NaOH (it is the sum of atomic masses of its elements):
Mr(NaOH) = Ar(Na) + Ar(O) + Ar(H) = 23 + 16 + 1 = 40 g/mol
So 1 M of NaOH has 40g
(2) Find the number of moles of 0.98g:
1 M has 40g.
x M has 0.98 g.
1M : 40 g = x : 0.98 g
x = 1M * 0.98 g : 40 g = 0.0245M
