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To determine the fraction of the hydrogen atom's mass that is in the nucleus, we have to keep in mind that
a Hydrogen atom has 1 proton and 1 electron.
Protons are in the nucleus while electrons are in electron shells surrounding the nucleus.
The mass of the nucleus will be equal to the mass of 1 proton and we can express the fraction as follows:

So, the fraction of the hydrogen atom's mass that is in the nucleus is
0,9995. That means that almost all the mass of this atom is at the nucleus.
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Answer:
Explanation:
There's no equation attached. What equation is it?
Answer is: the molar mass od sodium carbonate (Na₂CO₃) is 106.0 g/mol.
M(Na₂CO₃) = 2 · Ar(Na) + Ar(C) + 3 · Ar(O).
M(Na₂CO₃) = 2 · 23 + 12 + 3 · 16 · g/mol.
M(Na₂CO₃) = 46 + 12 + 48 · g/mol.
M(Na₂CO₃) = 106 g/mol; molar mass of sodium carbonate.
Ar is relative atomic mass (the ratio of the average mass of atoms of a chemical element to one unified atomic mass unit) of an element.
Answer:
Change in entropy for the reaction is
ΔS° = -268.13 J/K.mol
Explanation:
To calculate the change in entropy for the balanced reaction, we require the natural entropy of all the reactants and products in the reaction.
3 NO₂(g) + H₂O(l) → 2 HNO₃(l) + NO(g)
From Literature.
S°(NO₂) = 240.06 J/K.mol
S°(H₂O) = 69.91 J/K.mol
S°(HNO₃) = 155.60 J/K.mol
S°(NO) = 210.76 J/K.mol
These are the entropies of the reactants and products under standard conditions of 298.15 K and 1 atm.
Note that
ΔS° = Σ nᵢS°(for products) - Σ nᵢS°(for reactants)
Σ nᵢS°(for products) = [2 × S°(HNO₃)] + [1 × S°(NO)]
= (2 × 155.60) + (1 × 210.76) = 521.96 J/K.mol
Σ nᵢS°(for reactants) = [3 × S°(NO₂)] + [1 × S°(H₂O)]
= (3 × 240.06) + (1 × 69.91) =790.09 J/K.mol
ΔS° = Σ nᵢS°(for products) - Σ nᵢS°(for reactants)
ΔS° = 521.96 - 790.09 = -268.13 J/K.mol
Hope this Helps!!