chem 30 unit b part 2

Cathodes: When the half reaction at the cathode produces a metal due to reduction (which it usually does), the cathode will build up (increase in mass). As a general rule of thumb, cathodes tend to increase in mass (build up).

Anodes: When the half reaction at the anode involves the oxidation of the metal anode, the anode will dissolve (decrease in mass). As a general rule of thumb, anodes tend to decrease in mass.

Allows electrons to flow from anode to cathode

Allows the flow of ions between the half cells.

Site of the oxidation half reaction. Located in the half cell with the SRA. This piece of metal breaks down and gets smaller as the reaction occurs. (lose electron so solid pieces become aqueous ions)

Site of reduction half reaction, located in the half cell containing the SOA. This piece of metal builds up and gets bigger as the reaction occurs. (gain electron so aqueous ions become solid pieces)

Solid pieces of metal where half-reactions occur (must conduct electricity)

The cell is divided ingo two halves, or half cells. 

The redox reaction in voltaic cells is spontaneous.

In cells, the OA and RA are kepy away from each other so that electrons must flow through a wire to be transferred- this is an electric current. 

Each half cell has all the components present in a half reaction.

Sacrifical anode: A sacrifical anode is a metal that is deliberatley installed to protect a more valuable metal from corroding. How it works: the metal you are protecting is no longer the SRA, so it cannot be oxidized.

Paint: We can paint metals to offer them protection. If the metal is not exposed it cannot rust. 

Galvanizing: To galvanaize is to coat with zinc. You may have heard of galvanized nails which are used in fences or outdoor wood structures

Applying a current: The DC electric supplies the electrons to the OA trying to rust the metal so the metal dosent have to give them up.

A sealed electric cell with semi solid conductors 

Primary battery: a cell that cannot be recharged (cheap AA/AAA batteries)

Secondary battery: a rechargeable cell (cell phones/ car batteries)

Fuel cell: A cell where the fuel is continuously added (hydrogen fuel)

A process of purifying or refining a metal from an alloy. Extraction from metal ores through electrolysis. This is usually done with copper but can be a variety.

The process of coating or plating of one metal with another metal through electrolysis. This can be for decorative ourposes or for corrosion prevention.

Molten means liquid. This means that there is no water present. A molten ionic compound still splits into ions like an aqueous one but no water is listed.

If chlorine is binded to a group 1 atom, you always use it as ur SRA in an electrolytic cell.

A voltaic cell uses a spontaenous reaction to produce electricity. meanwhile, an electrolytic cell requires energy to make a non-spontaneous reaction happen. There is no salt bridge or porous cup in an electrolytic cell because with a non-spontaeneous reaction, we do not need to seperate the reactants.

The difference in energy between two points on a circuit per unit of charge. Voltage has a unit of volts (sometimes J/C). The joule is the unit of energy and the coulomb is the unit of charge. The purpose of building a voltaic cell is to create potential difference (voltage).

An inert electrode is an electrode (solid metal) that does not react (does not undergo oxidation or reduction). They are often used when there is no metal that corresponds to the ion or when using gases. Common inert electrodes are carbon and platinum. You can only replace something in the cell if it is not the SOA or SRA (INERT ELECTRODES ARE NEVER THE SOA OR SRA). Inert electrodes will always be the site of reduction reactions because they cant give away ions. Therefore, oxidation is impossible.  Ex. a carbon electrode cant give away zinc ions to a zinc solution. However, it can take in zinc ions by getting plated (this is rare tho)

Anions flow towards the anode (becomes more positive so needs negative charge to balance out)

Cations flow toward the cathode (becomes more negative so needs positive charge to balance out).

A voltaic cell is a device which spontaneously converst chemical energy into electrical energy. The chemical reaction is a redox reaction. The simplest voltaic cell consists of two electrodes in a conducting solution. The conducting solution (electrolyte- something that contains anions and cations) could be salt water, a potato, lemons, oranges, and even animal flesh.