For the purpose we will here use t<span>he ideal gas law:
p</span>×V=n×R×<span>T
V= </span><span>5.0 L
T= </span><span>373K
p= </span><span>203kPa
</span><span>
R is </span> universal gas constant, and its value is 8.314 J/mol×<span>K
</span>
Now when we have all necessary date we can calculate the number of moles:
n=p×V/R×T
n= 203 x 5 / 8.314 x 373 = 0.33 mole
The size v=masse/density
v= 4*pi*R^3
R=(3*masse/(4*pi*density))^(1/3)
R=1.9695 cm
John Dalton was a scientist who proposed that all matter consists of atoms. At this stage, no one had yet discovered neutrons and the nucleus. As a result, Dalton's model consisted of a single atom i.e. the atom was the smallest object.
A mass spectrometer is an instrument that is able to see what is inside an atom. Scientists have been able to prove that the item is not the smallest object in the world. Atoms are made up of smaller objects called protons, neutrons and electrons.
We can, therefore, safely conclude that data from mass spectrometry has helped modern scientists to make modifications to Dalton's model. <span>
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Explanation:
Hi for this one u just need to remember and use the equation.

then u find mr of potassium which is 39.1.
then u do

you get the answer as 0.5115 write ur answer to 3 significant figures which will be 0.512 moles .
hope this helps :)