English Vocabulary Flash Cards - Chemical Formulas @ englishpdf.com and englishteststore.com File 040 C H2 acetylene C2H3Cl vinyl chloride C H3 O2 − acetate ion C H4 ethylene C2H4Cl2 ethylene dichloride C H4 O2 acetic acid C2H5Br bromoethane C2H5NH2 ethylamine