# write the molecular formula for a compound with the possible elements C, H, N and O that exhibits a molecular ion at Mr-84.0948. Exact Masses of the Most Abundant Isotope of Selected Elements Isotope Natural abundance (%) H 99.985 1c98.90 14N99.63 Exact mass 1.008 12.000 14.003 15.995 99./6 Molecular formula C4H6NO X (In the order CHNO, with no subscripts)

Question

I am not sure how to work this problem.