Mr. Nkosi, I have a question regarding the S.H.E (Standard Hydrogen Electrode). I understand that the hydrogen electrode is used as a reference for calculating the potential difference across a cell for the two electrodes used and that this is similar to how other objects are used as a reference in life. An example of this is that there is a lump of metal in Paris upon which chemists and physics initially defined the kilogram to be the mass of that specific lump of metal and thus, the mass of different objects back in the day were calculated relative to the mass of that lump of metal (i.e. the lump of metal was used as a reference) -- obviously today we have better measurement systems in place so we don't constantly have to compare things to this specific metal in Paris (or just outside of Paris I believe). Anyway, so that's my understanding of a reference. So in the same way, since the potential difference can only be measured between two points or with regards to electrochemistry, between two half cells, it doesn't make sense to state the potential difference of just one-half cell because there would be no difference. You can also think of this in terms of an electric circuit - it makes sense to compare the potential difference between two points in the circuit, but it won't make sense to say that the potential difference is X volts at point Y. I also understand that when looking at the Standard Reduction Potential Table, since all of the half-reactions are written as reduction half-reactions, if the emf potential difference as depicted in the table is negative, it simply suggests that the half-reaction indicated would rather undergo oxidation as it has a greater reducing ability than the hydrogen half-cell when initially determining the Standard Reduction Potentials. And similarly, if the emf potential difference as conveyed in the table is positive, then that half-reaction will prefer to undergo reduction. However, my question is, when hydrogen was initially used in one-half cell and connected to another half cell containing a different metal, since a galvanometer shows the direction and magnitude of the current flowing through the external circuit, was it specifically due to the direction of current flow as indicated by the galvanometer that determined whether the platinum used in the hydrogen half cell acted like an anode or a cathode and thus, using the hydrogen potential difference as 0V, if the hydrogen half cell underwent reduction (and thus the other metal in the other half cell underwent oxidation), the half-reaction of the metal that underwent oxidation (obviously assuming that standard conditions were used) was noted and written down in the form of a reduction half-reaction with a negative emf value in the table? And then the same experiment was repeated with the hydrogen half cell and other metals. In other words, what I'm asking is: When the Standard Reduction Potential table was initially first created and the hydrogen half-cell was used as a reference against other half cells containing electrodes, was the ability to determine which half-cell underwent oxidation and which underwent reduction specifically due to the direction and magnitude of the current as shown on the galvanometer reading and thus, since the experiments were conducted under standard conditions, the results were recorded and formatted in a table? Apologies for the long question ;) 😇
Good morning once again Mr Nkosi. Hope you're doing well. I've noticed that on our physics formula sheet that we'll be given in finals, there are two tables of standard reduction potentials. Am I correct in saying that it doesn't matter which one we use as it seems to be that the only difference is how they are formated (Table 4A has the increasing strength of oxidising agents/increasing oxidising ability going from bottom to top whereas in Table 4B it goes from top to bottom)?
@@MlungisiNkosi Hi Mr Nkosi, I know this question isn't chemistry related, but do you know why a power vs current graph is a quadratic function? The question popped up in a past paper and I can't figure why. I thought it would be a straight line function going through the origin which suggests that power and current are directly proportional, but that doesn't seem to hold true. Thanks in advance.
@@coleabrahams9331 That's a fantastic question... P = I^2*R (I squared xR) Resistance is constant, thus making power proportional to the square of the current. That's a quadratic relationship
@@MlungisiNkosi Could we also state gold or rhodium as inert electrodes (along with graphite (carbon) and platinum) or will the examiners only accept graphite and platinum?
hi sir , by 8.2.3 , why dont we use the equation from the previous question ?please
Mr. Nkosi, I have a question regarding the S.H.E (Standard Hydrogen Electrode). I understand that the hydrogen electrode is used as a reference for calculating the potential difference across a cell for the two electrodes used and that this is similar to how other objects are used as a reference in life. An example of this is that there is a lump of metal in Paris upon which chemists and physics initially defined the kilogram to be the mass of that specific lump of metal and thus, the mass of different objects back in the day were calculated relative to the mass of that lump of metal (i.e. the lump of metal was used as a reference) -- obviously today we have better measurement systems in place so we don't constantly have to compare things to this specific metal in Paris (or just outside of Paris I believe). Anyway, so that's my understanding of a reference. So in the same way, since the potential difference can only be measured between two points or with regards to electrochemistry, between two half cells, it doesn't make sense to state the potential difference of just one-half cell because there would be no difference. You can also think of this in terms of an electric circuit - it makes sense to compare the potential difference between two points in the circuit, but it won't make sense to say that the potential difference is X volts at point Y.
I also understand that when looking at the Standard Reduction Potential Table, since all of the half-reactions are written as reduction half-reactions, if the emf potential difference as depicted in the table is negative, it simply suggests that the half-reaction indicated would rather undergo oxidation as it has a greater reducing ability than the hydrogen half-cell when initially determining the Standard Reduction Potentials. And similarly, if the emf potential difference as conveyed in the table is positive, then that half-reaction will prefer to undergo reduction.
However, my question is, when hydrogen was initially used in one-half cell and connected to another half cell containing a different metal, since a galvanometer shows the direction and magnitude of the current flowing through the external circuit, was it specifically due to the direction of current flow as indicated by the galvanometer that determined whether the platinum used in the hydrogen half cell acted like an anode or a cathode and thus, using the hydrogen potential difference as 0V, if the hydrogen half cell underwent reduction (and thus the other metal in the other half cell underwent oxidation), the half-reaction of the metal that underwent oxidation (obviously assuming that standard conditions were used) was noted and written down in the form of a reduction half-reaction with a negative emf value in the table? And then the same experiment was repeated with the hydrogen half cell and other metals.
In other words, what I'm asking is: When the Standard Reduction Potential table was initially first created and the hydrogen half-cell was used as a reference against other half cells containing electrodes, was the ability to determine which half-cell underwent oxidation and which underwent reduction specifically due to the direction and magnitude of the current as shown on the galvanometer reading and thus, since the experiments were conducted under standard conditions, the results were recorded and formatted in a table?
Apologies for the long question ;) 😇
Wow... Cole, this is phenomenal.Thank you for sharing.
why are we using platinum for the cathode? is it because there are more than 1 ions in that beaker
It is inert and conducts electricity...
3:11 Shouldn't the answer be "Iron"? Why is it platinum? Where did platinum come from?
Nvm you are right. Thanks
I'm glad you understood 😊
hi sir. does the order of how the net reaction is written matter? could i have written it as 2Fe^3+ + Zn -----> 2Fe^2+ + Zn^2+?
No the order doesn’t matter ☺️
@@MlungisiNkosi alrighty, thank you sir
Good morning once again Mr Nkosi. Hope you're doing well. I've noticed that on our physics formula sheet that we'll be given in finals, there are two tables of standard reduction potentials. Am I correct in saying that it doesn't matter which one we use as it seems to be that the only difference is how they are formated (Table 4A has the increasing strength of oxidising agents/increasing oxidising ability going from bottom to top whereas in Table 4B it goes from top to bottom)?
Yes it doesn't matter. The method I've taught works regardless of the table we use
@@MlungisiNkosi Okay, thanks so much
@@coleabrahams9331 my pleasure... You are incredible 😊
@@MlungisiNkosi Hi Mr Nkosi, I know this question isn't chemistry related, but do you know why a power vs current graph is a quadratic function? The question popped up in a past paper and I can't figure why. I thought it would be a straight line function going through the origin which suggests that power and current are directly proportional, but that doesn't seem to hold true. Thanks in advance.
@@coleabrahams9331 That's a fantastic question...
P = I^2*R (I squared xR)
Resistance is constant, thus making power proportional to the square of the current. That's a quadratic relationship
Can the answer for 8.1.2 also be graphite?
Yes it could 😉
@@MlungisiNkosi Could we also state gold or rhodium as inert electrodes (along with graphite (carbon) and platinum) or will the examiners only accept graphite and platinum?
Why platinum and not iron?
Platinum is an inert metal
8.2.2 I wrote platinum as the half cell- reaction 😭😭😭
Askies... Now you know 😊
I 🙋🏽♂️also need help with Mathematics 😭😭😭
I will help 😊
your lying\
Hhayi bo…