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.
First Day of Fall 2016. Get the date and time of the beginning of fall equinox and first day of fall 2016. The start of the fall season is observed in September in Northern Hemisphere. As the summer gets close towards month of August, many of you will be searching to know when the first day of autumn in year 2016 is.