Help
Options
Didn't know it?
click below
click below
Knew it?
click below
click below
Don't Know
Remaining cards (0)
Know
retry
shuffle
restart
0:00
Embed Code - If you would like this activity on your web page, copy the script below and paste it into your web page.
Normal Size Small Size show me how
Normal Size Small Size show me how
Electrode potentials
AQA A-level physical chemistry electrode potentials year 13
| Term | Definition |
|---|---|
| How batteries work | If 2 different metals (or potentially some non-metals with delocalised electrons) are placed in a solution of electrolytes (salts) then a current of electrons will pass from the more reactive metal (anode) to the less reactive metal (cathode) |
| Half-cell | When a rod of metal is dipped in a solution of ions of the same metal then equilibrium is set up where the metal acts as the reducer & the ions oxidisers E.g., Zn(s) <—> Zn2+(aq) + 2e- |
| Electrical potential | How readily electrons are released by a metal, this can’t be measured directly & can only be compared to that of other metals (potential DIFFERENCE or voltage) |
| Salt bridge | Absorbent line of material soaked in a saturated salt solution with each end in a different half-cell, this facilitated the transfer of ions without allowing the solutions to mix |
| Standard Hydrogen Electrode (SHE) | Hydrogen gas bubbled into solution of hydrogen ions with unreactive platinum electrode which reduces it back to hydrogen gas. Since none of the materials are conductive the SHE is defined as having an emf of 0 & is compared to half-cells to find their emf |
| EMF | ElectroMotive Force is the electrode potential of a cell. The more negative the better reducing agent, the more positive the better the oxidisation agent. The battery emf is the difference between cells measured in voltage |
| How cell notation works | Anode on the left, verticals solid line indicating phase boundary, double solid line indicating salt bridge, state symbols given, species with the highest oxidation state written next to salt bridge |
| How emf is calculated (+ way of remembering this) | The anode is nearly always on the left with the cathode on the right & electrons flowing right to the cathode. Total emf is calculated by taking the emf for the anode (left) from that of the cathode (right) Electrons (emf) (=) are a Right (-) Laugh |
| How to predict redox feasibility | In cases where the emf of both cells separately are both positive or negative, it is possible that the overall calculated emf is negative which means that the reaction isn’t feasible without redirecting electrons (e.g., Cu + Zn2+ — Zn + Cu2+ = -0.42V) |
Created by:
Study_B
Popular Chemistry sets