What is the percent composition of water in #Na_2S • 9H_2O?# Chemistry The Mole Concept Percent Composition 1 Answer anor277 May 23, 2017 #%H_2O# #~=# #70%# Explanation: #%H_2O="Mass of water"/"Mass of hydrate"=(9xx18.01*g*mol^-1)/(240.18*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 1361 views around the world You can reuse this answer Creative Commons License