D - Hydrates Flashcards
water of hydration
water is incorporated as an essential part of the crystal structure of the compound
it’s not just absorbed on the surface of the compound
how to remove water absorbed on the surface of a compound
gentle heating
water of crystallization
same thing as water of hydration
T/F The water of crystallization is bound directly to the ion
false
for the molar mass of a hydrate, do you include the molar mass of water
yes
efflorescence
spontaneously lose water to the atmosphere
cause of efflorescence
vapour pressure of water exerted by the hydrate is greater than the vapour pressure of the water in the atmosphere
desiccants
compounds that spontaneously absorb water from the atmosphere
hygroscopic
same thing as desiccant
cause of desiccant
vapour pressure of water exerted by the solid is less than the vapour pressure of water in the atmosphere
deliquescent
compounds that absorb so much water from the atmosphere that they dissolve in their own water of hydration
how to remove the water of crystallization from a hydrate
heated to a temperature at which the vapour pressure of water of the hydrate becomes greater then the pressure of water in the atmosphere
anhydrous form
when all of the water is gone from the compound
indication that the water of hydration has been driven off
1) colour change
2) form of the Crystal changes
3) it dissolves is in its own water of crystallization, which evaporates and leaves the anhydrous solid behind
how to calculate the mass of water in the sample
original mass of sample - mass of sample after heating
how to calculate the mass percent of water
mass of water in the sample/original mass of sample
how to calculate the moles of the anhydrite in the sample?
mass of the sample after heating/molar mass of the anhydrite
how to get moles of water in the sample
mass of water in the sample/molar mass of water
how to get empirical form of hydrate
ratio of moles of anhydrate to moles of water
what is a cation that emits a green flame
Cu 2+
what is a cat ion that emits a yellow flame
Na+
what is a cat ion that emits a Violet flame
K+
what is a cat ion that emits a green flame and has white precipitate
Ba 2+
what happens when water was added back to the copper sulphate Crystal?
it regenerated