Electrochemistry Flashcards

Flashcards on electrochemistry, covering redox reactions, electrolysis, conductivity, and related laws.

What type of reaction involves both oxidation and reduction?

Redox reaction

What is the loss of hydrogen called in terms of redox reactions?

Oxidation

What is the increase in oxidation number called?

Oxidation

What happens to a substance that undergoes reduction?

It gains electrons.

What is a substance that undergoes reduction and oxidizes another substance called?

Oxidizing agent or oxidant

What type of agent donates electrons?

Reducing agent or reductant

In the reaction Zn(s) + Cu2+(aq) -> Zn2+(aq) + Cu(s), which substance is oxidized?

Zn(s)

What happens to the oxidation number of a substance that is reduced?

It decreases.

In the reaction Cu(s) + 2AgNO3(aq) -> Cu(NO3)2(aq) + 2Ag(s), which substance is reduced?

Ag+

What type of displacement reactions are redox reactions?

Single displacement reactions

What are double displacement reactions in terms of redox?

Not redox reactions

What is the branch of physical chemistry dealing with the conversion between electrical and chemical energy?

Electrochemistry

What type of energy changes are spontaneous?

Negative Gibb's free energy change (ΔG < 0)

What is the device in which chemical energy is converted into electrical energy by spontaneous redox reaction called?

Galvanic cell or voltaic cell

In a galvanic cell, after the zinc ions solution builds up a positive charge and the copper solution builds up a negative charge without ion flow, what happens to the half cell reactions?

The half cell reactions will stop.

In a galvanic cell, is the reduction potential of reduction half cell reaction greater or lesser than oxidation half cell reaction?

Greater

What type of conductors relies on the movement of electrons?

Electronic or metallic conductors

What type of conductors relies on the movement of ions allowing current to pass?

Electrolytic or solution conductors

What typically happens to the resistance of a metal during the passage of current due to thermal motion of metal ions?

Resistance increases

What is a substance termed as, if when current is passed through the aqueous solution of the substance, and the substance decomposed of into its ions?

Electrolyte

What are substances called which are largely dissociated and form highly conducting liquid in water?

Strong electrolytes

What are substances called which are low conducting liquid formed to a small extent in aqueous solution?

Weak electrolytes

Does the extent of dissociation of an electrolyte increases or decreases with solution dilution?

Increases

Does the extent of dissocation of an electrolyte also increases or decreases with temperature an increase?

Increases

What device carriers the process of electrolysis or electrolytic decomposition?

Electrolytic cell or voltameter

Fill in the blank: In a voltameter, flow of electrons is from to _ and current will flow from to outside the electolyte.

anode to cathode, cathode to anode

Where are anions discharged during electrolysis?

Anode

Where are cations discharged during electrolysis?

Cathode

What type of products are known after products formed in reactions at cathode and anode?

Primary products

What products form due to further change in primary products?

Secondary products

What does the preferential discharge theory say about which ion is discharged?

The ion is discharged on one which occur low in the electrochemical series or which requires least energy or ions with lower discharge potential, then at either electrode, more than one type of ion is attracted.

Electrolysis applications are used in what major industries?

A wide range of industries

What process uses electrolysis to coat a superior metal over an inferior metal?

Electroplating

What did Michael Faraday's laws of electrolysis governs?

It governs substance (in ion form) are deposited on electrodes during electrolysis.

What does Faraday's first law state about amount of substance deposited or liberated?

The mass of any substance deposited or liberated at any electrode is directly proportional to the quantity of electricity passed.

Define electrochemical equivalent (ECE).

When a current of 1 amp. is passed through the mass of the ion deposited for a second.

What does Faraday's second law state about when the same quantity of electricity is passed through different electrolytes?

The masses of different ions liberated at the electrodes are directly proportional to their chemical equivalents (Equivalent weights).

What is electrical resistance' measurement expressed in?

ohms

What is the measurement of conductance in?

mho or ohm-1 or Siemens (S)

Fill in the blank: Conductivity is defined as the reciprocal of.

specific resistance