17 Matching Annotations
  1. May 2018
    1. E∘cell=RTnFlnK=(8.314JK⋅mol)(298.15K)n×96,485C/V⋅mollnK=0.0257Vnln

      I cannot follow how 0.0257/n turns into 0.0592/n i have tried several times but i don't understand the relation.

  2. Apr 2018
    1. Balance the following equation in acidic solution. Cr2O−27+HSO−3⇋Cr(H2O)5SO+4+SO−24Cr2O7−2+HSO3−⇋Cr(H2O)5SO4++SO4−2Cr_2O_7^{-2} + HSO_3^- \leftrightharpoons Cr(H_2O)_5SO_4^+ + SO_4^{-2} \nonumber Note: the above equation has a complex ion (Cr(H2O)5SO+4+SO−24Cr(H2O)5SO4++SO4−2Cr(H_2O)_5SO_4^+ + SO_4^{-2} that is involved with both half reactions, the chromium (which gets reduced) and the sulfur (which got oxidized). Answer

      What is the balanced equation??

    1. Question 1 Determine the cell voltage E at 250C, when [Fe2+]=[I-]=0.01M, [Fe3+]=0.02M.

      When [Fe2+] = what?? dont we need this concentration to solve Q??

    1. Question 1 Determine the standard potential (V) for the cell reaction.

      do we not need to multiply the Fe+3 resction by 2 - since it happens 2 times?? i get 2(.77)-.54 = 1

    1. Question 5 5.

      This problem need more info. to solve. the hint leads to a previous problem not included in this set.. it says k previous solved in #7...this is # 5...

    1. Question 3 Balancing the reactions in the acidic solution:

      Do we need to balance this equation first? have equal # of Cr & Oxygen on each side?? why would split this first?

    1. Question 2 What is the state of gold if the temperature is 1200 0C?

      if the temperature is less than that of the melting point, wouldn't this have to be solid??

      never mind - I didn't convert to kelvin : (

    1. Question 3

      I thought I set this up correctly but I subbed R for .008314 instead of 0.08206....can you suggest a way I can keep these values separated and when to use one over the other??

    1. What is Kc

      What is Kc; i understand Ka = K of acid, Kb = k of base, Kp = K of pressure....what is C...?

    1. (C)  0.1120M

      This value should be 1.120M It is correct in the hint, not in the multiple choice option.

  3. Sep 2017
    1. H2O(l)

      Are the other liquids that we should recognize? Are there rules for this like there is for solubility?

    2. BaI2+ H2SO4(aq)

      Some sets (h. NaOH, i. BaI) is not labeled as s,g or aq, Do we use solubility rules for reactants if not labeled?

    3. 3Mg+2

      in the product - same ? about labeling ion as s, g, or aq?? same in k. Ca+2... I understand that the solid has no charge, but what state the ionic form?

  4. Aug 2017
    1. The genius of Mendeleev's periodic table - Lou Serico

      at 2:10 the video mentions the predicted LOW melting point of an unknown element. What are the melting /boiling trends of the periodic table?