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Good Evening!
I just finished the first 60 GC questions in DAT Destroyer 2015, and I have selected four questions that I would appreciate your input on!
I didn't include question text in order to avoid violating copyright law, so I apologize in advance if this seems very confusing.
#3- So I understand why Delta H and Delta S are negative for the condensation of NH3. My issue is with the rationale for Delta G being negative. I had originally thought that Delta G would be negative since vaporization is spontaneous above the boiling point, and condensation is spontaneous below the boiling point? Is this line of reasoning accurate? The answer key states that there is a low enough temperature for Delta G to be negative; is this solely because the T is below the BP? Is there a mathematical way I could confirm this? I tried rearranging the Delta G = Delta H - T Delta S equation, but I'm not sure on exactly how to apply this here.
#27- The pH I initially calculated was 12, but the answer key states 7 due to the negligible concentrations of H+ ions. Is the following statement true then? Any acidic solution with an [H+] concentration below 1E-7, or any basic solution with an [OH-] concentration below 1E-7, has a pH of 7 since water is more acidic/basic?
#36- I approached this problem with the viewpoint that most metals (excluding Group 1 and Group 2) are Lewis Acids, and that acids are most soluble in bases. So, I reasoned that Ag+ would be the most soluble in the provided substance. Is this line of reasoning appropriate?
#58- This problem was solved with the concept of "valences"- I am a bit unclear on this, however. I understand that Mg can only be +2, and that Argon is non-reactive. I do not understand how to rule out C and Hg, however. Do you take advantage of the groups the elements are in to determine this?
Thank you in advance for all of your help!
I just finished the first 60 GC questions in DAT Destroyer 2015, and I have selected four questions that I would appreciate your input on!
I didn't include question text in order to avoid violating copyright law, so I apologize in advance if this seems very confusing.
#3- So I understand why Delta H and Delta S are negative for the condensation of NH3. My issue is with the rationale for Delta G being negative. I had originally thought that Delta G would be negative since vaporization is spontaneous above the boiling point, and condensation is spontaneous below the boiling point? Is this line of reasoning accurate? The answer key states that there is a low enough temperature for Delta G to be negative; is this solely because the T is below the BP? Is there a mathematical way I could confirm this? I tried rearranging the Delta G = Delta H - T Delta S equation, but I'm not sure on exactly how to apply this here.
#27- The pH I initially calculated was 12, but the answer key states 7 due to the negligible concentrations of H+ ions. Is the following statement true then? Any acidic solution with an [H+] concentration below 1E-7, or any basic solution with an [OH-] concentration below 1E-7, has a pH of 7 since water is more acidic/basic?
#36- I approached this problem with the viewpoint that most metals (excluding Group 1 and Group 2) are Lewis Acids, and that acids are most soluble in bases. So, I reasoned that Ag+ would be the most soluble in the provided substance. Is this line of reasoning appropriate?
#58- This problem was solved with the concept of "valences"- I am a bit unclear on this, however. I understand that Mg can only be +2, and that Argon is non-reactive. I do not understand how to rule out C and Hg, however. Do you take advantage of the groups the elements are in to determine this?
Thank you in advance for all of your help!