Simple Chem Thermo Questions

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1

<p>These might be really easy questions but I’m not that smart like you CC people so… yea </p>

<li>“An ammonium nitrate product dissolves in water and causes the solution to become cold.”<br></li>
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<p>Isn’t this process exothermic? because the solution releases heat and becomes cold… no? </p>

<p>The answer says it’s endothermic.</p>

<li><p>Sublimation, melting, boiling are all endothermic process.
and deposition, condensation, freezing are all exothermic process, right?</p></li>
<li><p>Among those two groups which one is spontaneous (+△S)?</p></li>
<li><p>10.0 is 2 sig figs, right?</p></li>
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2

<p>1) The solution became cold, so it lost heat. That heat has to go somewhere - the ammonium nitrate. Since the product took in heat, it is endothermic</p>

3

<p>but isn't ammonium nitrate a part of solution? </p>

<p>I thought the heat goes to the surrounding..</p>

4

<p>the solution is actually the surroundings believe it or not. the system would be the dissolving (if that makes any sense), and the surroundings lose energy, therefore the reaction is endothermic.</p>

<ol>
<li><p>yes.</p></li>
<li><p>the endothermic process have a positive S value. doesn't necessarily mean they aren't all spontaneous. the exothermic processes are spontaneous as well.</p></li>
<li><p>10.0 is 3 sig figs. _ _ . _
3 spaces. the 0's count b/c of the decimal point.</p></li>
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5

<p>thanks a lot but #1 did not make sense to me at all (sorry)</p>

6

<p>see it this way. The ammonium nitrate absorbs heat from the solution when it dissolves, making the latter cold, right? so its endothermic</p>

7

<p>the solution isnt the system..its neither a reactant nor product (for the most part)........it is merely a medium for the rxn...just as an empty 1-L container might be for a gaseous rxn...</p>