Which two changes of state can occur when a substance gains thermal
energy?

Adding enough thermal energy to a substance can cause a change of state to occur. The change of state from a solid to a liquid is called melting. When energy is added to an ice cube, the ice particles speed up as energy is absorbed. When the particles move fast enough, the solid ice melts and becomes liquid water

it is a good conductor

explanation:

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.