What is the percent by mass of water in barium bromide tetrahydrate #BaBr_2 * 4H_2O#? Chemistry The Mole Concept Percent Composition 1 Answer anor277 May 19, 2016 Approx. #20%# Explanation: #"Mass%" = "Mass of water"/"Mass of hydrate"xx100%# #=# #(4xx18.0*g*mol^-1)/(369.17*g*mol^-1)xx100%=??%# Answer link Related questions What is mole percent? Question #e2e8b Question #bc737 Question #bc73b Question #e2e8f Question #b9857 Question #b985b Question #fee41 Question #c5c01 Question #bc73f See all questions in Percent Composition Impact of this question 3062 views around the world You can reuse this answer Creative Commons License