Hello there!
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.
Have a nice day!
<span>Filtration, if its a precipitate that means its insoluble. </span>
Complete Question
The complete question is shown on the first uploaded image
Answer:
The correct option is 
Explanation:
From the question we are told that
the cell voltage for AD is 
From the data give we can see that

i.e 
In the same way we can say that

=> 

4. Number of atoms are conserved in chemical reactions
Answer:

Explanation:
1. Molar concentration
Let's call chloroform C and acetone A.
Molar concentration of C = Moles of C/Litres of solution
(a) Moles of C
Assume 0.187 mol of C.
That takes care of that.
(b) Litres of solution
Then we have 0.813 mol of A.
(i) Mass of each component

(ii) Volume of each component

(iii) Volume of solution
If there is no change of volume on mixing.
V = 15.08 mL + 59.70 mL = 74.78 mL
(c) Molar concentration of C

2. Molal concentration of C
Molal concentration = moles of solute/kilograms of solvent
Moles of C = 0.187 mol
Mass of A = 47.22 g = 0.047 22 kg
