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Flashcards in Test 4 Deck (44):
1

Acid-base buffer

A solution that resists changes in the pH when a small amount of either strong acid or strong base is added

2

common-ion effect

The sift in the position of an ionic equilibrium away from an ion involved in the process that is caused by the addition or presence of that ion

3

Henderson-Hasselbalch equation

An equation for calculating the pH of a buffer system.

4

buffer capacity

A measure of the ability of a buffer to resist a change in pH; related to the total concentrations and relative proportions of buffer components

5

buffer range

The pH range over which a buffer acts effectively

6

acid-base titration curve

A plot of the pH of a solution of acid versus the volume of base added to the solution

7

equivalence point

The point in a titration when the number of moles of the added species is stoichiometrically equivalent to the original number of moles of the other species

8

end point

The point in a titration at which the indicator changes color.

9

solubility-product

An equilibrium constant for a slightly soluble ionic compound dissolving in water.

10

complex ion

An ion consisting of a central metal ion bonded covalently to molecules and/or anions called ligands

11

ligand

A molecule or anion bonded to a central metal ion in a complex ion.

12

formation constant(Kf)

An equilibrium constant for the formation of a complex ion from the hydrated metal ion and ligands.

13

spontaneous change

A change that occurs by itself, that is , without an on going input of external energy.

14

entropy

A thermodynamic quantity related tot he number of ways the energy of a system can be dispersed through the motions of its particles

15

second law of thermodynamics

A law stating that a process occurs spontaneously in the direction that increases the entropy of the universe

16

third law of thermodynamics

A law stating that the entropy of a perfect crystal is zero at 0 K

17

standard molar entropy

The entropy of 1 mol of an ideal gas at standard temperature and pressure

18

standard entropy of reaction

The entropy change that occurs when all components are in their standard states

19

free energy

A thermodynamic quantity that is the difference between the enthalpy and the product of the absolute temperature and the entropy: G= H-TS

20

standard free energy of formation

The standard free energy change that occurs when 1 mol of a compound is made from its elements with all components in their standard states.

21

coupling of reactions

The pairing of reactions of which one releases enough free energy for the other to occur

22

adenosine triphosphate

A high energy molecule that serves most commonly as a store and source of energy in organisms

23

electrochemistry

The study of the relationship between chemical change and electrical work

24

electrochemical cell

A system that incorporates a redox reaction to produce or use electrical energy

25

half-reaction method

A method of balancing redox reactions by treating the oxidation and reduction half-reactions separately

26

voltaic cell

An electrochemical cell that uses a spontaneous redox reaction to generate electric energy

27

electrolytic cell

An electrochemical system that uses electrical energy to drive a non spontaneous chemical reaction

28

electrode

The part of an electrochemical cell that conducts the electricity between the cell and the surroundings

29

electrolyte

A substance that conducts a current when it dissolves in water

30

anode

The electrode at which oxidation occurs in an electrochemical cell. Electrons are given up by the reducing agent and leave the cell at the anode

31

cathode

The elected at which reduction occurs in an electrochemical cell. Electrons enter the cell and are acquired by the oxidizing agent at the cathode.

32

half-cell

A portion of an electrochemical cell in which a half-reaction takes place.

33

salt bridge

An inverted U tube containing a solution of a non reacting electrolyte that connects the compartments of a voltaic cell and maintains neutrality by allowing ions to flow between compartments

34

cell potential

The potential difference between the electrodes of an electrochemical cell when no current flows

35

voltage

The potential difference between the electrodes of an electrochemical cell when no current flows

36

electromotive force(emf)

The potential difference between the electrodes of an electrochemical cell when no current flows

37

volt

The SI unit of electric potential: 1V= 1 J/C

38

coulomb

The SI unit of electric charge. One coulomb is the charge of 6.242x1018 electrons; one electron posses a charge of 1.602x10-19C.

39

standard cell potential

The potential of a cell measured with all components in their standard states and no current flowing

40

standard electrode potential

The standard potential of a half-cell, with the half-reaction written as a reduction

41

standard reference half-cell

A specially prepared platinum electrode immersed in 1M H+ through which H2 gas at 1atm is bubbled.

42

Faraday constant

The physical constant representing the charge of 1mol of electrons: F= 96,485 C/mole e-

43

Nernst equation

An equation stating that the voltage of an electrochemical cell under any conditions depends on the standard cell voltage and the concentrations of the cell components

44

concentration cell

A voltaic cell in which both compartments contain the same components but at different concentrations