4. A. What is the percent by mass of water present in CoCl2.6H20?

B. Name the hydrate.

52.17%

using periodic table ... We get the molar mass respectively for C, O, Cl and H20. You get an answer as 207 by adding all of them. Then as we have 6 water molecules and we get 108. so we have to divide 108 and 207 then multiply the decimal with 100. we get 52.17%