Our best evidence and theoretical calculations indicate that the solar system began with a giant spinning system of gas and dust that scientists call .

Solar nebula

Explanation:

The theory of the origin of the solar system emanates from the believe that a dense giant spinning cloud of dust condensed to produce our solar system.

This cloud of dust is called the solar nebula.

the ideal gas law equation is as follows

pv = nrt

where p - pressure

v - volume

n - number of moles

r - universal gas constant

t - temperature

so if the pressure, volume and temperature are already known

we are left with n and r

since r is the universal gas constant that has a known fixed value then r too is known

so we are left with 'n'

once we know temperature volume and pressure

we can find the number of moles of gas present using the ideal gas law equation

this is not my own answer, this is an answer for the same question by the user blahblahmali. i do not claim ownership of this account.