lab practical study guide

Question 1

(buffers) the hydrogen ion concentration and the pH depend on the value of the …. and the ratio of the concentrations of ….

Answer 1

acid dissociation constant, Ka; acid and conjugate base

Question 2

(buffers) pKa + pKb=

Answer 2

14

Question 3

(buffers) experiment overview: in this experiment the pH of water and a number of solutions will be measured, and then acids and bases will be added to see how… Several buffer solutions of different pH values will be prepared and tested for their ability to

Answer 3

the pH is affected; resist change of pH

Question 4

(buffers) part 1: .. mL distilled water plus … drops HCl and … drops …
… mL NaCl plus … drops .. and .. drops …

Answer 4

20; 3; 3; NaOH; 20; 3; HCl; 3; NaOH

Question 5

(buffers) part 2: prepare a buffer using … mL of .. M…. and .. mL … M…
add 3 drops … and then ….
repeat with a buffer of … mL … M …. and … mL … M …

Answer 5

10; .1M; HC2H3O2; 10; .1; NaC2H3O2
HCl; NaOH;
10; .1; NH3; 10; .1; NH4Cl

Question 6

(buffers) part 3: unknown solid acid of mass … to … g; dissolve in … mL of distilled water; pour … mL into a second flask and add 2 drops phenolphthalein; titrate with … M …; add the same volume of water as titrant used to titrate to flask 1 to make the ….. of the two solutions the same

Answer 6

1.8; 2.0; 150; 75; .2; NaOH; concentrations

Question 7

(buffers) part 3 (continued): combine … mL of weak acid solution with .. mL of conjugate base solution to make a buffer. measure pH, ths is also the …
create buffer of assigned pH and test effectiveness

Answer 7

10; 10; pKa

Question 8

(electrochemistry) an electrochemical cell is produced when an oxidation reaction and a reduction reaction occurs …., and their resulting electron transfer between the two processes occurs through an ….

Answer 8

spontaneously; external wire

Question 9

(electrochemistry) the oxidation and reduction reactions are physically separated from each other and are called …

Answer 9

half-cell reactions.

Question 10

(electrochemistry) a half-cell can be prepared from almost any metal in contact with a

Answer 10

solution of its ions

Question 11

(electrochemistry) since each element has its own electron configuration, each element develops a different …., and different combinations of oxidation and reduction half-cells result in different …. for the completed electrochemical cell

Answer 11

electrical potential; voltages

Question 12

(electrochemistry) the standard reduction potential is the voltage that a half-cell, under standard conditions develops when it is combined with the

Answer 12

standard hydrogen electrode

Question 13

(electrochemistry) the more positive the reduction potential, the …. the reduction

Answer 13

easier

Question 14

(electrochemistry) a spontaneous cell (a battery) can be constructed if two half-cells are connected internally using a …, and externally using a ….

Answer 14

salt bridge; metallic connector

Question 15

(electrochemistry) the symbol | refers to a

Answer 15

phase boundary

Question 16

(electrochemistry) the symbol || indicates a

Answer 16

salt bridge between the two ion solutions

Question 17

(electrochemistry) nernst equation:

Answer 17

E=E° - .0592V/n * logQ

Question 18

(electrochemistry) part 1: a standard table of reduction potentials is constructed; microscale half-cells are constructed by placing a piece of metal into a … M solution of its …. for each metal in the series (Cu2+, Fe3+, Pb2+, Mg2+, Ag+, Zn2+). the half-cells are connected by a salt bridge constructed of a strip of .. soaked in a solution of ….

Answer 18

1 M; ions; filter paper; potassium nitrate

Question 19

(electrochemistry) part 1 (continued): the … half-cell is chosen as the reference standard and is assigned a value of 0.00 volts. voltage values should correlate with those found in …, but they will differ by the value of …. for the …

Answer 19

zinc; published tables; E°; zinc electrode

Question 20

(electrochemistry) part 2: the nernst equation is applied to the voltage measurement of a cell with ….. A solution of …. M Cu2+ is prepared by a …., and the voltage of the cell Zn(s) | Zn2+ (1.0 M) || Cu2+ (0,0010 M) | Cu(s) is measured and is then compared to that calculated from the ….

Answer 20

nonstandard copper ion concentration; .0010; serial dilution; nernst equation

Question 21

(electrochemistry) part 3: the solubility product constant of AgCl is determined from the …. and the …. in which the zinc half-cell is connected to a solution containing a trace of … in a … M solution of …

Answer 21

nernst equation; voltage of a cell; Ag+ ions; 1.0; NaCl

Question 22

voltaic/galvanic cell: apparatus that produces … directly from the chemical energy released in a ….

Answer 22

electrical energy; redox reaction

Question 23

electrochemical cell: a device capable of either generating …or ….through the introduction of ….energy

Answer 23

electrical energy from chemical reactions; facilitating chemical reactions; electrical

Question 24

electrolytic cell: A type of chemical cell in which the flow of …. causes a …. to occur.

Answer 24

electric energy from an external source; redox reaction

Question 25

Electrode potential is defined as the potential of a cell consisting of the…. acting as a cathode and the … acting as an anode.

Answer 25

electrode in question; standard hydrogen electrode

Question 26

Potential of a cell is the…. between the two electrodes of a ….

Answer 26

electric potential difference; voltaic cell

Question 27

oxidizing agent: a substance that tends to bring about … by being …

Answer 27

oxidation; reduced

Question 28

reducing agent: a substance that tends to bring about … by being …

Answer 28

reduction; oxidized