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.
On the Vernal exuinox it is the first day of spring (March 20th) and on an Atumnal equinox its the frist day of fall   The â¦ sun is vertically overhead the Equator, this occurs twice per year, once with the northen hemisphere heading towards the sun, and once with it heading away from the sun.he spring Equinox occurs on April 21 st. The fall Equinox is on September 21 st. The summer Solstice occurs on June 21 st and the winter Solstice occurs on December 21 st. 2 people found this useful.