You're a very odd man who obviously just likes a scrap, or just tries to use flawed science to defy logic (or perhaps more likely flawed logic to defy science).
Q. Can we assume that the laws of physics and chemistry are universal, no matter where you are?
A. Generally yes, there is no reason to believe that chemicals will react differently just because you're on Mars.
Chemistry and physics do work universally, within certain parameters, those parameters (atmosphere, gravity, known chemical compositions) are all known about so unless there's something that we don't know and have been unable to detect (some kind of cloaked wormhole or twist in space-time?) it is a fair assumption.
When Chris says "We are still learning about physics and chemistry here on Earth which constantly changes our understanding (and thus our "laws" of physics and chemistry)." Don't be misled, most of the time we discover *new* things which expand our understanding (carbon nano tubes, using diamond for computer chips, new plastics etc.) rarely (if ever, in modern times) do the "laws" change, I suspect burning hydrogen in the presence of oxygen will never produce chicken gravy.
Chris isn't a complete idiot, It's a valid question to ask, "will this work the same off earth?" but thanks to the thousands of experiments carried out in space and on the moon and on mars, the answer is "can't see any reason why not", so Chris, your question has been answered and "will this work the same off earth?" is now as valid as "will this work the same on Brighton beach or in the corner of my living room?"
I suspect that Chris likes to promote doubt into science, is it a fact to say "if I drop a hammer off a building it will fall to the ground?", the laws of physics say yes, so some would state it's a fact, it will hit the ground, but what Chris is saying is that it's possible that the hammer could just hang there, and no amount of arguing will make him change his mind that it might not hit the ground.
ps. There's no god either.