The number of mercury atoms required to produce 3.49 L of H2 gas according to the equation would be 1.89 x 
From the balanced equation of the reaction:

2 moles of Hg are required to produce 1 mole of the H2 gas.
3.49 L of H2 gas was produced and the density of the gas is 0.0899 g/L
Recall that: density = mass/volume
Mass of the H2 gas = density x volume
= 3.49 x 0.0899
= 0.3138 g of H2 gas
Mole of 0.3138 g of H2 gas = mass/molar mass
= 0.3138/2
= 0.1569 mole
Since the ratio of Hg to H2 according to the equation is 2:1, it means that the mole of Hg is twice the mole of H2.
Thus, mole of Hg = 0.1569 x 2
= 0.3138 mole
According to Avogadro, 1 mole of a substance = 6.022×10^23
0.3138 mole would be:
0.3138 x 6.022 x 10^23
= 1.89 x 
More on the number of atoms in molecules can be found here: brainly.com/question/19036641
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The molality of a solute is equal to the moles of solute per kg of solvent. We are given the mole fraction of I₂ in CH₂Cl₂ is <em>X</em> = 0.115. If we can an arbitrary sample of 1 mole of solution, we will have:
0.115 mol I₂
1 - 0.115 = 0.885 mol CH₂Cl₂
We need moles of solute, which we have, and must convert our moles of solvent to kg:
0.885 mol x 84.93 g/mol = 75.2 g CH₂Cl₂ x 1 kg/1000g = 0.0752 kg CH₂Cl₂
We can now calculate the molality:
m = 0.115 mol I₂/0.0752 kg CH₂Cl₂
m = 1.53 mol I₂/kg CH₂Cl₂
The molality of the iodine solution is 1.53.
So for that one I’m going to go with True