Redox HELP!!! thanks you

[jack_chay]

oh ok thank you

[jack_chay]

A galvanic cell is set up by combining a half cell of a zinc
rod in a solution of zinc nitrate with a half cell of metal X in
a solution of X nitrate. The zinc electrode is found to be the
negative electrode. Would you expect metal X to be more or
less reactive than zinc? Explain your reasoning.

I know that zinc has to be the stronger reductant and the metal has to be the stronger oxidant, but I don't know wether it is more or less reactive

[jgoudie]

If you look at the electrochemical series you will see that gold is up the top and potassium is down the bottom.  You might know that gold is a very un reactive metal as you can find it in the ground (if you are lucky) and you know that potassium is a very reactive metal (when you looked at alkali metals in water in year 9/10 or this video: http://www.youtube.com/watch?v=pPdevJTGAYY)

This lets you know that the higher on the electrochemical series the metal appears, the less reactive it is.

This should help you out.

A galvanic cell is set up by combining a half cell of a zinc
rod in a solution of zinc nitrate with a half cell of metal X in
a solution of X nitrate. The zinc electrode is found to be the
negative electrode. Would you expect metal X to be more or
less reactive than zinc? Explain your reasoning.

I know that zinc has to be the stronger reductant and the metal has to be the stronger oxidant, but I don't know wether it is more or less reactive

[spectroscopy]

whats the purpose of a salt bridge and why do we use potassium nitrate as a solution for it

[Yacoubb]

whats the purpose of a salt bridge and why do we use potassium nitrate as a solution for it

The salt bridge is used to actually complete the circuit and connect the two half-cells to form the galvanic cell. K+ ions move to the cathode, where reduction occurs (i.e. gain of electrons), and NO3- ions move to the anode, where oxidation occurs (i.e. loss of electrons).

[spectroscopy]

ah ok, but why do we need to use voltmeters to order recudtants from strongest to weakest? and like how do we do it just by the voltage can someone explain that please?

sorry to hijack your thread jack_chay but redox is hard LMAO

[psyxwar]

ah ok, but why do we need to use voltmeters to order recudtants from strongest to weakest? and like how do we do it just by the voltage can someone explain that please?

sorry to hijack your thread jack_chay but redox is hard LMAO

Voltage is just a measure of electrical potential differences - as you know, the higher the voltage between two cells, the more spontaneous that reaction. So having these standard reduction potentials enables us to see what species will react, and whether or not such a reaction will be spontaneous.

As voltage is a difference though, you need something to be measure it against. The standard hydrogen electrode (S.H.E.) is arbitrarily assigned 0V and the standard reduction potentials of half cells are calculated by connecting them to the S.H.E. and the potential difference between the two measured and this voltage is given to the half cell being measured (as the S.H.E. is at 0V). A voltmeter is simply the device used to measure this voltage.

Hence, based on this we can order them from strongest to weakest reductants. Think of the standard hydrogen electrode as just being a pace stick of sorts, that every other half cell can be measured against.

On another note S.H.E. is a great band, check them out.

[Implore01]

Voltmeter measures the voltage, which gives the values in the electrochemical series, the values are relative to H2 hydrogen gas which is 0.00 V, hope that clears things up

[lzxnl]

Standard Electrode Potentials are a measure of how spontaneous a reaction is. The higher the standard electrode potential of a cell, the more favoured the forward reaction is.