True or false: theories are sometimes replaced as a result of new science.

True

Explanation:

Theories are not laws and so new scientific evidence could render them as untrue. For example, the big bang theory on how the universe has started is just a theory. Current evidence backs it up, but if future evidence disproves it, the theory will be replaced by a different one.

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.