What is the mass of 1.71 ✕ 1023 molecules of h2so4?

The equation for calculating a mass is as follows:

m=n*M

Molar mass (M) we can determine from Ar that can read in a periodical table, and a number of moles we can calculate from the available date for N:

n (H2SO4) = N/NA

n (H2SO4) = 1.7*10²³ / 6 * 10²³

n (H2SO4) = 0.3 mole

Now we can calculate a mass of H2SO4:

m (H2SO4) = n*M = 0.3 * 98 = 27.8 g