5 Sem, 2 Exam

Question 1

Which metals can occur with different charges?

Answer 1

transition metals, d-block

Question 2

Old definition of an oxidation and a reduction?

Answer 2

An oxidation was an addition of an oxygen atom

A reduction was the subtraction of an oxygen atom

Question 3

What is the modern definition of a redox reaction?

Answer 3

A reaction in which an exchange of electrons occurs.

Electron transfer reaction.

Question 4

What is the modern definition of an oxidation and a reduction?

Answer 4

Oxidation: a loss of an electron
Reduction: a gain of an electron

Question 5

What are two mnemonics for remembering if oxidations and reductions are a gain or loss of electrons?

Answer 5

LEO GER - Loss of electrons is oxidation, gain of electrons is reduction
OIL RIG - oxidation is loss, reduction is gain

Question 6

What is a reductant? Which column is it in the KME redox table?

Answer 6

A reducing agent, an electron donor, left column

Question 7

What is a oxidant? Which column is it in the KME redox table?

Answer 7

A oxidizing agent, an electron acceptor, right column

Question 8

What are the rules of oxidation numbers?

Answer 8

Pure elements and metals are always 0.
Fluorine (F) has -I in compounds.
Oxygen (O) has -I in compounds except F2O and H2O2.
Hydrogen has +I in compounds except in metal hydrides (e.g. CaH2).
Group 1 metals have +I in salts.
Group 2 metals have +II in salts.
Group 13 metals have +III in salts.
Mononuclear ions have ox.# equal to charge.
Bonds between equal elements in compounds do not count.

Question 9

2x_______ agents ______(verb).

Answer 9

Reducing agents oxidize.

Oxidizing agents reduce.

Question 10

If reducing agent is above and only above oxidizing agent, then reaction will run __________.

Answer 10

“Downhill”

Question 11

The equilibrium of a redoc reaction is always on the side of the ___________________.

Answer 11

The weaker oxidizing and reducing agents.

Question 12

The ___________ reaction will run completely.

Answer 12

“Downhill”

Question 13

When different metals are put into different salt solutions, then metals are the _______ and the salt solutions are the _________.

Answer 13

reducing agents,

oxidizing agents

Question 14

The standard electrode potential table is derived from measuring electric potential from putting ____________.

Answer 14

metals into salt solutions

Question 15

_____________ are in the left column of the standard electrode potential table (their strength ________ downwards)

Answer 15

Reducing agents,

decreasing

Question 16

_________ are in the top left corner of the standard electrode potential table.

Answer 16

strong base metals

Question 17

Base metals ______ with acid as they will react with the _______ ____.

Answer 17

corrode,

reductant, H3O^+

Question 18

_______ do not corrode with “normal” acids as they are beneath ______ in the redox table and it would be a _____reaction

Answer 18

Noble metals,
H3O^+,
“uphill”

Question 19

_______ are in the right column of the standard electrode potential table (their strength ________ downwards)

Answer 19

Oxidizing agents,

increasing

Question 20

Reactions going from the _____ to the _____ are oxidations

Answer 20

left, right

Question 21

Reactions going from the ___ to the _____ are reductions

Answer 21

right, left

Question 22

The decomposition of metals through oxidation?

Answer 22

corrosion

Question 23

Gold and platinum can be dissolved by _______, which is a mixture of concentrated ___ and concentrated ___ in a ratio of ___.

Answer 23

aqua regia,
HNO3, HCL,
1:3

Question 24

The oxide of an oxidizing metal forms a coating and prevents the rest of the metal from oxidizing?

Answer 24

Passivation

Question 25

Liquids which conduct electricity (while they undergo a chemical reaction) and consist of dissolved ions?

Answer 25

Electrolytes are

Question 26

Positively charged ______ migrate to the negative ______, where the ______ happens.

Answer 26

cations, cathode, reduction

Question 27

Negatively charged ______ migrate to the positive _____, where ______ happens.

Answer 27

anions, anode, oxidation

Question 28

What is electrolysis often used for?

Answer 28

to gain pure metals from salts

Question 29

It is not possible to electrolyze dissolved salts containing metals above ___________ because the _____ already electrolyzes before the salts at a lower voltage.

Answer 29

H2 + 2OH^- ==> H2O, | water

Question 30

An electrolysis under the absence of water with molten salts (containing metals above H2 + 2OH^- ==> H2O) so that the water doesn’t react first?

Answer 30

Fused-salt electrolysis

Question 31

_______ is an aluminum ore found in Guinea and Australia, it contains white alumnia (Al2O3), iron and sometimes titanium.

Answer 31

Bauxite

Question 32

_________ always have a lower melting point than in their pure form.

Answer 32

Contaminated compounds

Question 33

Connecting two containers that are separated by a porous membrane and contain metals and their dissolved ions with a wire results in a flow of electricity. The circuit has a current as long as there is metal in the oxidizing cell or as long as there are dissolved ions in the reducing cell

Answer 33

Galvanic cell (Daniell cell with copper electrode, copper sulfate solution, and sulfuric acid, a zinc electrode)

Question 34

What is the mnemonic to remember on which side the reduction happens and on which side the oxidation happens in a Daniell/galvanic Cell?

Answer 34

REDCAT - reduction at cathode | OXAN - oxidation at anode

Question 35

Who was the frog and nerve experiment performed by?

Answer 35

Luigi Galvani

Question 36

Who explained the frog and nerve experiment and constructed the first battery?

Answer 36

Alessandro Volta

Question 37

Batteries (Galvanic cells) use ________ and are therefore not rechargeable.

Answer 37

spontaneous redox reactions (“downhill”).

Question 38

Galvanic cells can be ___________ to increase the voltage.

Answer 38

connected in series

Question 39

Anions migrate to the ________, cations migrate to the _______.

Answer 39

anode, cathode

Question 40

The more positive the value for the standard reduction potential the more likely the substance is to reduce.

Answer 40

Is this true for our table too?