Unit 3 Flashcards
what is electrochemistry
Electrochemistry is a branch of chemistry that deals with reactions that convert chemical energy into electrical energy and vice versa.
what are practical uses of electrochemistry (3)
- chemical reactions in batteries
- corrosion of metals
- electrical impulses in our bodies
what is oxidation
the loss of electrons
what is an example of oxidation
apples turning brown when they get exposed to the air
what is reduction
the gain of electrons
what is an example of reduction
iron metal ruts because of it’s reaction with oxygen
how do you tell which one is being reduced
the one that starts with the charge is reduced because it gain electrons
how do you tell which one is being oxidized
the one that starts with no charge is oxidized because it lost electrons
how do you know which one is the reducing agent
the one that was oxidized is the reducing agent
how do you know which one is the oxidizing agent
the one that was reducing is the oxidizing agent
what is a redox reaction
a chemical reaction with both a reduction and oxidation
give an example of a redox reaction
Mg(s) + Cu2+(aq) –> Cu(s) + Mg2+(aq)
what is the purpose of a half reactionary
to make it easier to follow the transfer of electrons they make them into half reactions so oxidation and reduction can be represented seperatly
in a redox reaction why does the oxidizing agent undergo reduction
In a redox reaction the oxidizing agent accepts the electrons from the reactant being oxidized. Since the oxidizing agent is gaining electrons it is reduced.
do you include the front numbers when doing the half reactions
yes
what is the purpose of the galvanic cell
a device that converts chemical energy into electrical energy through redox reactions
how does it work
the reactants in the redox reaction do not come into direct contact with each other, so the electrons are forced to travel through an external wire, or circuit.
what are half-cells
The compartments of a galvanic cell, including the electrodes.
who developed the galvanic cell and when
In 1836, John Frederick Daniell developed a galvanic cell
what electrodes
A conducting substance through which electrons can enter or leave the cell.
what is the anode (2)
- The anode is the negative electrode where oxidation takes place.
- It is the source of electrons, and the negative terminal of the galvanic cell.
what is the cathode (2)
- The cathode is the positive electrode where reduction takes place.
- It receives electrons and is the positive terminal of the galvanic cell.
what is a electrolyte
A substance that conducts electricity when it is dissolved in water.
what is a porous barrier or salt bridge
Allows the flow of ions to maintain a neutral charge in the half-cells, while preventing the ions in the cathode half-cell from coming in direct contact with the anode.
what is the external circuit/wire
Connects the anode and the cathode together to allow electrons to flow from the anode to the cathode in an external circuit.
what is the voltmeter/load
A voltmeter can be connected into the external circuit to measure the amount of electricity produced. Alternatively, an electrical load, such as a light, can be connected into the circuit.
how does the activity series work
In a galvanic cell, electrons always flow from the anode to the cathode in the external circuit. The anode, the metal that is oxidized, is the more reactive metal of the two based on the activity of series of metals.
how do you complete the galvanic cell
- To complete the circuit of the galvanic cell, the two half-cells must be connected, but the contents of the half-cells not allowed to mix. - To complete the circuit the half-cells are usually connected by a porous barrier, or a salt bridge.
what does the salt bridge do
The porous barrier or salt bridge allows the flow of ions to maintain a neutral charge in the half-cells, while preventing the copper (II) ions from coming in direct contact with the zinc electrode.