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Chemistry Forums for Students => Undergraduate General Chemistry Forum => Topic started by: Judy on January 17, 2022, 11:37:09 AM

Title: Entropy
Post by: Judy on January 17, 2022, 11:37:09 AM

Which response includes all of the following processes that are accompanied by an increase of entropy?

I) NaCl(s) ----H20---> Na+(aq) + Cl-(aq)

II) CaSO4(s) ---H20---> Ca +2(aq) + SO4 -2(aq)

III) KNO3 (s) ---H20---> K +1(aq) + NO3 -1(aq)

the answer is I and III.

Why does II decrease, just like I and III, they turn from 1 to 2 molecules?

Title: Re: Entropy
Post by: Babcock_Hall on January 17, 2022, 11:39:37 AM

What is different about the ions in II vs. I and III?  Once you identify this difference, think about what the difference affects.

Title: Re: Entropy
Post by: Judy on January 17, 2022, 10:33:49 PM

Is it because I and III are belong to IA group while II belong to IIA group? If so, why IIA group tend to decrease in entropy when dissolved in water? Thanks.

Title: Re: Entropy
Post by: Babcock_Hall on January 18, 2022, 09:34:44 AM

How many charges does the calcium ion have?  How many charges does the sodium ion have?  Same questions for sulfate vs. chloride.  Besides the ions, what else is present in a solution?  How might this something else behave in response to the presence of the ions?