Chemical formula tells us the number of atoms of each element in a compound. It contains the symbols of the atoms of the elements present in the compound as well as how many there are for each element in the form of subscripts.
A cover letter is an accompanying letter that serves as
the introduction to your resume. No resume should be
sent without one. The cover letter is individualized for
each position for which you are applying. It is an
extension of your resume and reflects your knowledge
of the employer’s needs.
No, it is not a correct sentence.
The mistake is in the word <em />worse - you need to use the superlative (final) form of the adjective. Bad - worse - worst. So the correct answer would actually be:
Deciding to go to Barcelona was the worst decision I ever made.