The notation  hydrated compound ânH2O , where n is the number of water molecules per formula unit of the salt, is commonly used to show that a salt is hydrated. The n is usually a low integer, though it is possible for fractional values to occur. For example, in a monohydrate n is one, and in a hexahydrate n is 6.
When does spring start? How you define the first day of spring depends on whether you follow the astronomical or meteorological seasons. This year, spring will take place between March 20 and June 21, if you use the astronomical method. But it starts slightly earlier, between March 1 and May 31, if you follow the meteorological calendar.
We have shared here the first days of all the season with winter, first day of spring, summer and first day of fall 2016. Then check the first day of autumnal equinox 2016 in Southern Hemisphere (Australia, New Zealand and South Africa), you can refer to our post on first day of spring 2016.