When liquid H2O is chemically separated in a scientific investigation it forms H2 gas and O2 gas. If the number of hydrogen and oxygen molecules does not change through the equation, then the mass will Select one:
decrease from reactants to products.

stay the same from reactants to products.

increase from products to reactants.

increase from reactants to products.

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.