Solid inorganic compounds that have bound water molecules attached to the atoms, either coordinated to the molecule or directly to the metal atom. The water generally will not affect the chemistry (after all a lot of reactions take place in aqueous solvents anyway), but may affect the colour of the compound.
It is termed water of crystallisation; and as the name implies the water molecules are bound in the lattice when crystallised.
When writing a formula, it will look something like MgSO4.7H2O, meaning magnesium sulfate has 7 water molecules bound to it, and is a hepta-hydrate.
The water can be removed simply by heating it up.
Technically the compound is "wet" even though it will look and feel like a dry powder.
Anhydrous compounds are ones that do not contain any coordinated water.
Anhydrous compounds that will coordinated a large number of water molecules are widely used to "dry" mixtures where a little water may contaminate an organic solvent as the water binds to the substance, but the substance remains in a powdered form, often clumping, so is easily removed by filtration.
mass
Na2SO4.10H2O
There are a number of ways you could tell when a hydrated crystal starts to become dry. It will start to lose its shine for example.
An acid, when dissolved in water yields H+ ions. In water they would be hydrated and be H3O+
Pouring water on it because when it is heated it turns to an endothermic reaction and the hydrated part is boiled put of the compound it is then Anhydrous copper sulphate. When you add water it is hydrated again and this is an exothermic reaction. Which can get extremely hot so don't pour it on your hand and then hydrate it.
mass
Na2SO4.10H2O
The color of an anhydrous compound is sometimes different from the hydrated compound.
It is calcium chloride .But it exists as CaCl2.2H2O in its hydrated state.
hydrated silicon dioxide
By rusting hydrated iron(III) oxide is formed.
Rust is hydrated iron(III) oxide.
There are a number of ways you could tell when a hydrated crystal starts to become dry. It will start to lose its shine for example.
An acid, when dissolved in water yields H+ ions. In water they would be hydrated and be H3O+
No, Epsomite is simply a hydrated form of Epsom Salts, which are themselves a compound - Magnesium Sulphate, MgSO4. It is therefore a compound of the elements Magnesium, Suplhur and Oxygen.
H2o is a compound because it retains its own property.
Pouring water on it because when it is heated it turns to an endothermic reaction and the hydrated part is boiled put of the compound it is then Anhydrous copper sulphate. When you add water it is hydrated again and this is an exothermic reaction. Which can get extremely hot so don't pour it on your hand and then hydrate it.