Conversion gain in mixer?

I have several questions about conversion gain in mixer

1.Does onversion gain mean power gain OR voltage gain ?

2.Does power gain always normalized to 50 ohm reistance?

3.Do we need to match the load impedance of the mixer to 50ohm if we need to connect the mixer to an off-chip filter? If so,Pout means the power delivered to filter or the power on the load impedance?

Hi
1- power is popular
2- it depends on your load
3- you must match it with the impedance that it can find from it's output.
regards