I am a chemist. Would I be able to teach the course?

Yes, but clearly you will need to spend some time in preparation. The actual science explanations do not demand biology or physics beyond GCSE. Most science teachers find that the more exciting change in teaching a course like this is the more open-ended discussion and relation of scientific knowledge to issues in the real world. This can involve some teaching techniques (such as small group discussion, role play, communication of an argument to express an opinion) that are less common in science labs than other classes.

Some teachers have found that dividing the course between a physical scientist and a life scientist works well. You might consider this if you feel uncomfortanle with the life sciences - there are some other benefits to team teaching.