# Tom Blum
#
# This program introduces the concept of vectors
# instead of having a bunch of atomic weight variables 
# e.g. c=12.011, h=1.008, etc
# we can have a vector with the atomic weights for 
# carbon, hydrogen, nitrogen and oxygen -- in that order
atomic_wt <- c(12.011, 1.008, 14.007, 15.999)
#
# the c function c() seen above creates a vector 
# and in R is known as "concatenting" 
#
# Next we can mke another vector with the "subscripts" 
# for caffeine C8H10N4O2
#
caff_subsc <- c(8, 10, 4, 2)
# 
# the product of the two vectors will multiply 12.011 by 8, 
# 1.008 by 10, etc. 
#
caff_at_wt = caff_subsc * atomic_wt
caff_at_wt
#
# if we sum all of these up we have the molecular 
# weight of caffeine
#
caff_mole_wt = sum(caff_at_wt)
caff_mole_wt
# 
# we can find the percentage of each atom by weight 
# by dividing the weights for each element by the 
# overall weight nd multiplying by 100
#
caff_perc_wt = caff_at_wt / caff_mole_wt * 100
caff_perc_wt