ok...so i did a lab in chem. and i dont understand two of the questions..well first things first...we are determining the formula for magnesium sulfate...
why should the mass of the evaporating dish be measured immediately after it cools, and not later?
i dont know that one...
and it said to use a desiccator but my class didnt...
how would my results be affected if we would have used a desiccator when cooling the evaporating dish and contents?
PLEASE HELP!!!
2007-12-12 13:00:13 · 3 answers · asked by Anonymous in Science & Mathematics ➔ Chemistry
i also meant to ask why it is necessary to let the evaporating dish cool before measuring the mass?
and thanks sooooo much to the others that have already helped me with my questions! your heroes!
2007-12-12 13:22:44 · update #1
I believe the reason is that MgSO4 will asorb water so you don't want to measure the weight of the water absorbed just the MgSO4.
BTW, look up the word desiccator, and you'll see it is a substance that absorbs water to protect some thing else.
2007-12-12 13:03:38 · answer #1 · answered by feanor 7 · 0⤊ 0⤋
A desiccator ensures that moisture does not accumulate in your sample which will increase it's mass.
You probably had to weigh your evaporating dish immediately after so that moisture would not affect the resulting mass of your experiment.
In a desiccator there is a drying agent that repels moisture/water.
2007-12-12 13:07:01 · answer #2 · answered by Anonymous · 0⤊ 1⤋
You are actually determining the formula of the hydrate of magnesium sulfate (it is 7 H2O).
If you wait too long, the MgSO4 will start to pick up moisture from the air and gain back the mass that you drove off while evaporating.
If you had a desicator, you would place your sample inside and minimize the risk of water being picked up again.
2007-12-12 13:04:47 · answer #3 · answered by reb1240 7 · 1⤊ 0⤋