Here is a site my buddie has to help you. Well co-owner..
https://www.quora.com/Why-is-fresly-prepared-FeSO4-required-for-the-ring-test
Data:
p (pressure) = 81.8 kPa = 81.8*10³ Pa ≈ 8.07 atm
v (volume) = ? (in L)
n (number of mols) = 0.352 mol
R (Gas constant) = 0.082 (atm*L/mol*K)
T (temperature) = 25ºC converting to Kelvin, we have:
TK = TC + 273 → TK = 25 + 273 → TK = 298
Formula:

Solving:




When we go to periodic table, Sulfur is
an element that has 16 protons and 16 electrons.
when there is 18 electrons, with number of two electrons more than protons. This makes it an ion and
the ion has a -2 charge.
So when there is16 protons, 18 neutrons, and 18 electrons the symbol is S⁻².
The neutrons have no charge but they add only mass to the
elements. So when there is 16 neutrons, it doesn't change the symbol of ion.
Precise and Accurate mean the same thing. I would consider measuring more than once to get a precise or accurate measurement.