Oops, it doesn't look like 'chemistry week started out as a single day' is a national day..

Other days

Latina Equal Pay Day

Ormille Day

Kiss A Brunette Day

African Immigrant And Refugee Hiv And Hep Awareness Day

Lisp Day

Emoji Day

Self Appreciation Day

Tell Ur Crush You Like Them Day

Carpenters Day

Eat What You Want Day