Question about Sennheiser MOMENTUM 2 Wireless

First question: Yes.
Second question: Yes, if you have a corresponding amplifier. Here I refer you to the technical data from Sennheiser. http://de-de.sennheiser.com/momentum-k...
If the headphones are active, i.e. run on battery power, the impedance (internal resistance) of the headphones drops and smaller amplifiers such as mobile phones can drive them more easily. In case your battery is empty, the headphones will still work with the included 3.5mm jack cable, but the impedance will increase to 480Ω. This does not prevent playback with the vast majority of players, but it does lead to a different listening experience.
In my opinion: Better than most, even in passive mode.