To become a Chemical Engineer in BitLife, you will first need to create a character who has decent smarts. Having decent smarts will aid you in the first step in becoming a Chemical Engineer in BitLife, which is to go to college. If you want to get high smarts for your character, the easiest way is to re-roll your character.
To re-roll your character, simply keep re-creating characters until you get one that has the stats you desire. Once you have high smarts, keep aging up until you graduate high school. After graduating, you will need to apply and enroll in college with a Chemical Degree.
After graduating college, you can become a Chemical Engineer by looking for an Engineer I job under the Job Tab. However, not any Engineer Job will work, and you will need to look for one that has Chemical Engineer Career listed as the career on the job card.
How to go to college for a Chemical Degree in BitLife
You can go to college for a Chemical Degree by taking a student loan or getting a scholarship if you have high smarts. Both options will appear under the event pop-up that appears after graduating high school. The easiest of the options is to get a student loan, but you will need to get a job quickly, so you don't go into debt.
For this reason, Scholarships are the better route but are harder to obtain if you don't have high smarts. There are two ways to get a Scholarship, having high smarts and asking your parents to pay. Asking your parents to pay rarely works, so it's better to ensure you have high smarts when creating your character.
If you have high smarts, you can choose the option that grants you a scholarship for free. That said, Either method for enrolling will work regardless, so pick one, and when you enroll, find Chemical Degree under the list of options. Doing so will allow you to go to college for a Chemical Degree in BitLife.