Many chemical salts come as hydrated crystals. That is, there is a specific ratio of water molecules associated with the salt crystals e.g. MgSO4.7H2O (called Magnesium sulphate heptahydrate FW = 246.5) has 7 water molecules to every Mg2+ and SO42- ion pair.
But it is also possible to get MgSO4 as an anhydrous powder (without water) FW =120.4. Once dissolved in water these salts have the same chemical properties but in the solid state they obviously have a different FW.
You are given a recipe for a buffer that contains 5% (w/v) MgSO4.7H2O. However, you only have MgSO4 anhydrous available to you. How much MgSO4 anhydrous do you need to make 0.5L of the buffer with the same molar concentration as in the recipe? Show your calculations.
(can not do any of it pls help)
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