Calculate the number of molecules of hydrogen that are required to completely react with 75.9l of oxygen at stp. the product of this reaction is water. show all work including balanced equation.

2H₂ + O₂ = 2H₂O
n(O₂)=V/Vm, V-volume, Vm=22,4 dm³/mol at standard condition.
n(O₂)=75,9 dm³/22,4dm³/mol=3,39 mol
n(O₂):n(H₂)=1:2, n(H₂)=6,78 mol
N=n·Na(Avogadro number), N(H₂)=6,78 mol·6·²³ 1/mol = 40,68·10²³ molecules

 = 40,68·10²³ molecules

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Mass % of the solution = 7.1067 %

Explanation:

Given :

Molarity of nitric acid solution = 1.85 M

Density of the solution = 1.64 g/mL

Molarity of a solution is defined as the number of moles of solute present in 1 liter of the solution.

Lets, consider the volume of the solution = 1 L

Thus,

Moles of nitric acid present in the solution:

So,

Moles of Nitric acid  = 1.85 moles

Molar mass of nitric acid = 63 g/mol

The mass of Nitric acid can be find out by using mole formula as:

Thus,  

Mass of Nitric acid = 116.55 g

Also,

Given : Density = 1.64 g/mL

Also, 1 L = 10³ mL

Volume of the solution is 1000 mL

So, mass of the solution:

Mass of the solution  = 1640 g

Mass % is defined as the mass of solute in 100 g of the solution. The formula for the calculation of mass % is shown below:

So,

Mass % = 7.1067 %