Hi Monica,

We're always working on adding new content, so quizzes and unit tests are bound to be added to the Chemistry and Physics courses at some point in time! As far as when that will be, I'm not yet sure.

To stay up to date with the new content is being added, make sure to keep an eye on the News and Updates forum: https://khanacademy.zendesk.com/hc/en-us/community/topics/200170394

Hope this helps! Please let me know if you have any further questions.