They are both challenging subjects (chemistry 1 is by far easier than chemistry 2, concept wise)
The course is taught exceptionally well, however it is extremely content heavy and moves at a fast pace, especially compared to first year biology. The lecturers do talk very fast and deliver an exuberant amount of content in every lecture (Alessandro's quantum lectures in chemistry 2).
The key thing about chemistry is that knowing is not enough. You need to understand the concepts because simple memorisation of facts and lecture notes will leave you struggling in the exam, as they are testing how well you can apply concepts, not how well you can remember a specific example.
You can pass the subject as long as you stay on top of the work and make sure that you have a good set of notes. Make sure that your notes are in your own terms, not just copied straight from the lectures. Tutorials are the most valuable resource possible, especially with the right tutor (I had Sonia) as they know exactly what concepts challenge most students and they will ensure that there is thorough explanations made.
The practicals are not too challenging for the most part (one or two of them can be a little bit stressful) and with a bit of work beforehand, you can walk into the practicals pretty confident. The demonstrators will also show you how they want the lab report set out and they outline anything that may be difficult to understand.
There are help sessions available for the first year subjects and I highly recommend attending. There will either be a lecturer or a senior tutor in there to help you and they are brilliant at explaining concepts.
The exam can be quite daunting as it is worth 74%. The markers will tend to try and find any way to give you marks (even as far as marking work that has been crossed out), so as long as you attempt questions, even if you know the calculations are wrong, you will be rewarded.