My interview was extremely relaxed. I wasn't asked any technical questions at all, although I have heard that this has changed. We just had a chat about why I wanted to study Chem Eng, why Imperial, and that was pretty much it.
He pretty much told me he'd give me an offer at the end of the interview and told me to make sure I work hard to get my A* in maths.
I've heard that nowadays some interviewers give a list of topics and you can choose a topic to discuss with the interviewer e.g thermodynamic cycles
Lecturers can vary. Some are very good at teaching; they're organised, they are engaging, very clear and can make the class fun. Others, not so much. I'd say that the majority of the teaching is pretty good though.
You do labs for the first 3 years of the course in groups of 3 or 4.
In first year, we did 2 lab experiments a week for one month which was insane. We had labs everyday (excluding Wednesday) from 2-5pm. It was very hectic and there often wasn't enough time inbetween labs to write up your lab book. At the end of this you had to produce a lab report (individual) on your final experiment. Sometimes you could be lucky to get an easy experiment, sometimes not. They've reduced the number of experiments now so it should be okay.
Second year was similar but with a reduced number of experiments so you go more in depth into them.
Third year was actually the most interesting. You are given a topic and you have to design an experiment plan, decide how and what you want to investigate and are given a lot more freedom in the lab. A professor and a Phd student help you out for this.
You're given a month and at the end you have to produce a group report.
Hope it helps
Are you planning on applying this year?