Moles of ZnSO4 = Mass/Mr
= 2/(65.4 + 32.1 + (16 x 4))
= 0.012383.... mol
Since there is no chemical equation provided, I will assume that the ratio of ZnSO4:Li2CO3 is 1:1
Therefore there are 0.012383 mil of Li2SO4 as well
So the mass would be Moles x Mr = 0.012383.... x ((6.9 x 2) +32.1 + (4x16))
= 1.360 g of Li2SO4 produced