SAT BARRONS CHEMISTRY HELP PLEASE

Test Preparation
1

<p>Hey guys, I would really appreciate it if one of you could explain #19 of Practice Test #3 in the Barrons Chemistry book.</p>

<p>I don’t really understand why that reaction happens</p>

<p>Thanks</p>

2

<p>post question</p>

3

<p>A) Brownian Movement
B) Litmus Paper Reaction
c) Phenolphtalein reaction
d) Dehydration
e) Deliquescent</p>

<ol>
<li>The reason why a blue crystal of CuSO4 . 5H2O turns white when heated</li>
</ol>

4

<p>The answer is D</p>

5

<p>CuS04 5H2O gets dehydrated when you heat it… the loss of water causes the substance to turn from blue to white.</p>

6

<p>Can you explain why is turns from blue to white? Or is it just something I need to know?</p>

7

<p>Water is blue, yes? So when it evaporates, the resultant crystal is white. :P</p>

8

<p>^ good way to remember, but probably not the mechanics.
I don’t really know what the mechanics are, so I think it’s just something you have to know. I think it’s actually commonly used in the dehydration lab (I’ve done it twice)! </p>

9

<p>Deliquescent means that it attracts water to its surface. CuSO4 o 5 H20 changes color because the water is removed from it by dehydration? If you’ve done the lab, you’ve probably seen it, so just have confidence and go with it!</p>

10

<p>Thanks guys, I haven’t taken AP Chem so I’m having trouble withe the lab stuff and the descriptive chemistry. Do you guys have any links or videos that could help me? I’m studying from Barrons and Sparknotes right now</p>