True or false? the radioactive nature of a specific element does not change even if the element is chemically combined with another element in a compound

yes

Explanation:

even in combined state, radioactive elements continue to emit radiation spontaneously. For instance RaCl2 is still radioactive because of the radium content of the compound. This is applied positively in radionuclides used to study chemical reactions or uptake of certain elements in then body.

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.

the answer is minerals.