How many molecules does 10 grams of sulfuric acid contain?

Given:
m (H2SO4) = 10 g

To find:
N (H2SO4) -?

1) Using the periodic system of D.I.Mendeleev, calculate the molar mass of H2SO4:
M (H2SO4) = Mr (H2SO4) = Ar (H) * N (H) + Ar (S) * N (S) + Ar (O) * N (O) = 1 * 2 + 32 * 1 + 16 * 4 = 98 g / mol;
2) Calculate the amount of substance H2SO4:
n (H2SO4) = m (H2SO4) / M (H2SO4) = 10/98 = 0.102 mol;
3) Calculate the number of H2SO4 molecules:
N (H2SO4) = n (H2SO4) * NA = 0.102 * 6.02 * 10 ^ 23 = 0.614 * 10 ^ 23 = 6.14 * 10 ^ 22.

Answer: The number of H2SO4 molecules is 6.14 * 10 ^ 22.