this is still regarding the experiment of composition of hydrates:
CuSO4 pentahydrate
2006-09-25 04:59:57 · 5 answers · asked by ethene 1 in Science & Mathematics ➔ Chemistry
Changes in air currents caused by the heated dish can effect the scales. An analytical balance (measuring mass to the nearest 0.0001 grams is very sensitive).
The mass of the empty evaporating dish or the tared dish with the original Copper (II) sulfate pentahydrate was performed with the dish at ambient room temperature. After the dish is heat for a sufficiently long time to drive off the hydrated water, the dish must be allowed to cool to room temperature before the final mass reading.
If you are allowed to do this, heat an empty evaporating dish and then place it on a balance and watch the mass fluctuate. This might even impress your teacher.
2006-09-25 05:02:52 · answer #1 · answered by Richard 7 · 73⤊ 0⤋
Evaporating Dish
2016-10-06 06:17:51 · answer #2 · answered by shimp 4 · 0⤊ 0⤋
Because if it is not cool there may be more evaporation of liquid going on that will change the mass that is left on the dish.
2006-09-25 05:02:39 · answer #3 · answered by Rich Z 7 · 0⤊ 1⤋
Probably because a hot item makes the air around it move, throwing off the scale.
2006-09-25 05:01:45 · answer #4 · answered by Pseudo Obscure 6 · 1⤊ 1⤋
if it's still hot you get currents of hot air making the scale bounce all over the place
2006-09-25 05:08:08 · answer #5 · answered by shiara_blade 6 · 1⤊ 0⤋