Saturday, May 07, 2005
Honors Electro Questions
Just want to post a reply to one of the questions about the worksheets (speaking of which, the Table "L" referred to on the worksheets is really Table "N" in our reference Tables):
How do you determine whether or not a reaction will occur in water? I think that the worksheets are using different reference tables because all of my calculations for voltage have been off, but only because they are using different numbers. ?
Answer:
K+ (aq) + I- (aq) + Cl2 (g) --> K+ (aq) + Cl- (aq) + I2 (s)
How do you determine whether or not a reaction will occur in water? I think that the worksheets are using different reference tables because all of my calculations for voltage have been off, but only because they are using different numbers. ?
Answer:
The reaction in water means the reaction in "aqueous solution". That means that the salt listed is dissolved into its aqueous ions. Then, you just look at which type of single replacement reaction is occurring: metal replaces metal cation or non-metal replaces non-metal anion.
Example:
KI (aq) + Cl2 (g) --> I2 (s) + KCl (aq)
K+ (aq) + I- (aq) + Cl2 (g) --> K+ (aq) + Cl- (aq) + I2 (s)
when you connect the REACTANTS I- and Cl2 on Table N, the line goes downhill which means that the reaction is spontaneous...i.e. chlorine is a more active (attracts electrons better) non-metal than iodine. Note that the K+ (aq) is just a spectator ion because it cannot be oxidized ( K2+ would be waaay less stable than K+).
The worksheet book uses mostly the same electrode potentials (some differ by 0.01 V) so if you are only off by a couple of hundredths, that is fine.
Let me know if you have any further questions.
Mr.C.
Let me know if you have any further questions.
Mr.C.
# posted by C @ 3:29 PM 
