You can compare your trial mark as the minimum mark you'd get for HSC, so most probably you'll get higher than your trials, for chemistry, most probably 80+ ? and for bio 85+ ?
A lot of those will probs be low B6 but remember that school mark does not necessarily equal HSC marking. And I disagree with the above comment for things like chem- HSC marking is pretty intense and chances are you'll get lower in HSC than trials if you haven't improved in the meantime
Don't be too hasteful in making your decisions for all we know OP's school rank could be in the 200's/300's, but if solely based on these marks if you could replicate exactly this in the HSC you'd be getting alot of Band 6's imo
I did my internal school trial for 2U maths and got absolutely penetrated by it (Below year average) and then did the CSSA paper without any revision and got 87. Same conditions, same markers (student numbers were used - CSSA did not count towards final internal mark... ._.)
You'll need to get a larger sample size of raw marks to get a better indication thereof.
You can't really indicate what you'll get in HSC based only on trial marks. I got ~85% in my Chemistry trial but their marking guidelines were nothing like the actual HSC.
In Chemistry (example), it's usually something like this is what you need for 5/5, this is what you need for 4/5, this is what you need for 3/5 and sometimes, missing one criterion can drop you to 2/5 - this happened to be in a few past papers and only adding one line could've gotten you 2 extra marks.