Class Six

Question 1

what is a redox reaction

Answer 1

a reaction in which the oxidation numbers of any of the reactants change

Question 2

when an atom loses electrons, it undergoes..

Answer 2

oxidation (oxidation # increases)

Question 3

when an atom gains electrons, it undergoes..

Answer 3

reduction (oxidation # decreases)

Question 4

LEO the lion says GER

Answer 4

lose electrons = oxidation

gain electrons = reduction

Question 5

what is a reducing agent

Answer 5

an atom that is oxidized in a reaction (loses electrons)

Question 6

what is a oxidizing agent

Answer 6

an atom that gains electrons

Question 7

what happens to the anode

Answer 7

it gets oxidized and its electrons travel to the cathode

Question 8

where does reduction take place in a galvanic cell

Answer 8

at the cathode

Question 9

if the cell voltage is positive, the reaction is..

Answer 9

spontaneous

Question 10

if the cell voltage is negative, the reaction is..

Answer 10

non spontaneous

Question 11

the more negative the reduction potential..

Answer 11

the weaker the reactant is as an oxidizing agent

the stronger the product is as a reducing agent

Question 12

the more positive the reduction potential..

Answer 12

the stronger the reactant is as an oxidizing agent

the weaker the product is as a reducing agent

Question 13

Nernst equation

Answer 13

Question 14

free energy change equation for a redox reaction

Answer 14

delta G = - (n)FE

Question 15

value of faraday

Answer 15

96,500 C

Question 16

what is a concentration cell

Answer 16

galvanic cell with identical electrodes but different ion concentrations

Question 17

what is an electrolytic cell

Answer 17

it uses an external voltage source to create an electric current that forces a non spontaneous redox reaction to occur

Question 18

how do electrons move in galvanic cell

Answer 18

from the anode to cathode

Question 19

Faraday’s law of electrolysis

Answer 19

the amount fo chemical change is proportional to the amount of electricity that flows through a cell

Question 20

time based cell calculation formula

Answer 20

I = nF/t

Question 21

main difference between galvanic and electrolytic cells

Answer 21

electrolytic cells have an external power source (galvanic is spon)

Question 22

where does plating occur

Answer 22

at the cathode

Question 23

in a galvanic cell, the cathode is..

Answer 23

positive

Question 24

in an electrolytic cells the cathode is..

Answer 24

negative

Question 25

where does pitting occur

Answer 25

at the anode

Question 26

in a galvanic cell, the anode is..

Answer 26

negative

Question 27

in an electrolytic cell, the anode is..

Answer 27

positive

Question 28

what happens in alpha decay

Answer 28

alpha particle is emitted out of the parent (2 pro & 2 neu)

parents atomic number goes down by 2 and mass number goes down by 4

Question 29

beta - decay

Answer 29

when there are too many neutrons in the nucleus

converts neutron → proton which is ejected

atomic number is now 1 greater

Question 30

beta + decay

Answer 30

when there aren’t enough neutrons → converts proton into a neutron and a positron

atomic number is now 1 less

Question 31

electron capture

Answer 31

takes an electron from closest shell and uses it to convert proton → neutron

atomic number is reduced by 1

Question 32

gamma decay

Answer 32

relaxing from an excited state releases a gamma photon

does not change the identity of the nucleus

just an expulsion of energy

Question 33

what is the mass defect

Answer 33

mass of combined nucleus is less than the sum of the masses of all its individual nucleons

Question 34

positive mass defect

Answer 34

seen in stable nucleus

Question 35

Einstein’s equation for mass energy equivalence

Answer 35

E = (delta m)c²