Chemistry is fairly difficult but not too difficult.
It requires some memorisation of content but not anywhere near as much as biology. It requires analytical and mathematical skills, but not so much as maths or physics.
You shouldn't struggle doing chemistry without doing maths, but you will definitely find A2 chemistry easier if you do maths (not required but helps).
If you enjoy these subject then take them. I'm not sure about history and geography, but biology and chemistry are enjoyable and interesting subjects.
I'm not sure about law, but you should be ok for medicine if you take biology and chemistry to A2.
I've done A-level maths and am doing A2 further maths, biology, chemistry and physics.