eng Science and Education Publishing World Journal of Chemical Education 2375-1657 2020-08-17 8 4 141 149 10.12691/wjce-8-4-1 WJCE2020841 article Andrew M. Kelley 1 Stephanie Garcia 1 David R. Khan 1 William G. Ambrose 2 Jason C. Yarbrough 2 James D. Woodyard 2 James C. Espinosa jespinosa@wc.edu 3 Department of Chemistry and Physics, West Texas A&M University, 2501 4th Avenue, Canyon, Texas 79016, United States Department of Mathematics, West Texas A&M University, 2501 4th Avenue, Canyon, Texas 79016, United States Department of Physical Sciences, Weatherford College, 225 College Park Dr., Weatherford, Texas 76086, United States This paper discusses our ¡°Dry Lab¡± experiment where students are shown the procedure for calculating the nominal and precise M+ values of a compound. However, our main focus deals with the detailed step-by-step process for calculating the precise M+1 and M+2 values of a compound, as well as any of its higher order M+ values, when its molecular formula is known. http://pubs.sciepub.com/wjce/8/4/1/wjce-8-4-1.pdf calculation of M⁺ calculation of M⁺¹ calculation of M⁺² organic chemistry mass spectroscopy instrumental analysis