$ sudo apt-get remove chemeq 

Uninstall chemeq including dependent package

If you would like to remove chemeq and it's dependent packages which are no longer needed from Ubuntu,

$ sudo apt-get remove --auto-remove chemeq 

Use Purging chemeq

If you use with purge options to chemeq package all the configuration and dependent packages will be removed.

$ sudo apt-get purge chemeq 

If you use purge options along with auto remove, will be removed everything regarding the package, It's really useful when you want to reinstall again.

$ sudo apt-get purge --auto-remove chemeq 

See Also,