Explanation:
Starting moles of ethanol acid = 0.020 mol
At the equilibrium 50 % of the ethanol acid molecules reacted
∴ Moles of ethanol acid reacted = 0.020 mol * 50 %/100 %
= 0.010 mol
Moles of ethanol acid remain = 0.020 mol + 0.010 mol = 0.010 mol
Moles of the product
gas formed are calculated as
0.010 mol CH3COOH * 1 mol
/ 2 mol CH3COOH
= 0.005 mol 
Therefore at the equilibrium total moles of gas present in the vessel are 0.010 mol CH3COOH and 0.005 mol 
That is total gas moles at equilibrium = 0.010 mol + 0.005 mol = 0.015 mol
Now Calculate the pressure :
0.020 mol gas has pressure of 0.74 atm therefore at the same condition what will be the pressure exerted by 0.015 mol gas
P1/n1 = P2/n2
P2 = P1*n2 / n1
= 0.74 atm * 0.015 mol / 0.020 mol
= 0.555 atm
Answer:-
As we can see from the graphical data,
The distance covered by all the four runners is the same 5 km.
Among the four athletes, Athlete P covers the distance in under three hours.
It is the minimum time taken among the four athletes.
Thus Athlete P covers the 5 km distance in the minimum amount of time.
We know that speed = 
Since time taken for P is minimum, his speed is the maximum. P ran the fastest.
Time taken by Q = 4.5 hours.
Speed of Q = 
= 
= 1.1 km/ hr
Time taken by R = 6 hours.
Speed of R = 
= 
= 0.8 km/ hr
to have the closest number rounded up
"18) the element with the most stable nucleus and smallest mass per particle is:A) uranium.B)argon C) helium."