Can you please help me solve this Chemistry problem!?

Question

How many atoms of mercury are required to produce 3.49 L of H2 gas (density= 0.0899 g/L) according to the balanced chemical reaction.

2 Hg (l) + 2 HNO3 (aq) --> Hg2(NO3)2 (aq) + H2 (g)

Answer 1

2Hg (l) + 2HNO₃ (aq) --> Hg₂(NO₃)₂ (aq) + H₂ (g)

density = mass/volume

mass = density x volume

mass = (0.0899 g/L)(3.49 L)

mass = 0.313751 g

mw of H₂ = 2(1.008) = 2.016 g H₂

mol = (0.313751)/(2.016 ) = 0.15563 mol H₂

stoich fraction of H2 to Hg₂ = 1/2

0.15563 mol H₂(2 mol Hg/1 mol H₂)(6.022 x 10 ²³ )= 1.9 x 10²³ atoms of Hg

Answer 2

3.49 L H₂ x 0.0899 g / L x 1 mol H₂ / 2 g = 0.157 mols H₂

Using dimensional analysis along with the stoichiometry of the balanced equation:

0.157 mols H₂ x 2 mols Hg / 1 mol H₂ x 6.022x10²³ atoms Hg / mol = 1.89x10²³ atoms Hg