ch 20 & 21 test

Question 1

electrochemistry

Answer 1

the study of the relationships between electricity and chemical reactions. It includes the study of both spontaneous and non-spontaneous processes

Question 2

oxidized

Answer 2

oxidation number increases for an element. Losses electrons.

Question 3

reduced

Answer 3

oxidation number decrease for an element. Gains electrons.

Question 4

voltaic cell

Answer 4

a spontaneous redox reaction, electrons are transferred and energy is released

Question 5

anode

Answer 5

(-) where oxidation occures. e^- on right side.

Question 6

cathode

Answer 6

(+) where reduction occures. e^- on left side.

Question 7

metal deposition

Answer 7

as the electrons reach the cathode, cations in solution are attached to the now negative cathode.

Question 8

Ecell°=

Answer 8

E°red(cathode)-E°red(anode)

Question 9

the more positive the value of E°red

Answer 9

the greater the tendency for reduction

Question 10

the strongest oxidizing agents

Answer 10

have the most positive reduction potential

Question 11

the strongest reducer

Answer 11

have the most negative reduction potentials

Question 12

a redox rxn is sponatenous if

Answer 12

• E°cell is +
• delta G is -
• K is greater than 1

Question 13

batteries

Answer 13

portable self-contained electrochemical power source that consists of one of more volatic cells.

Question 14

alkaline battery

Answer 14

the most common primary battery

Question 15

lead-acid battery

Answer 15

reactants and products are solids. made with lead and sulfuric acid (hazards).

Question 16

Ni-Cd and Ni-metal hybride batteries

Answer 16

• lightweight, rechargeable
• hydrides replace Cd since Cd is toxic

Question 17

Lithium-ion battery

Answer 17

rechargeable light; produce more voltage than Ni-based batteries.

Question 18

fuel cells

Answer 18

when a fuel is burned, the energy created can be converted to electrical energy.

Question 19

hydrogen fuel cells

Answer 19

-in this cell, hydrogen and oxygen form water.
-the cells are twice as efficient as combustion.
-the cells use hydrogen gas as the fuel and oxygen from the air.

Question 20

corrosion

Answer 20

is oxidation and often leads to structural and mechanical failure. The common name is rusting.

Question 21

cathodic protection

Answer 21

a metal is sacrificed based on the standard reduction potentials.

Question 22

sacrificial anode

Answer 22

used to prevent corrosion of iron underground pipes. Is attached to the pipe. The anode is oxidized before the pipe.

Question 23

electrolysis

Answer 23

non-spontaneous chemical reactions can now occur if outside electricity is used to drive the reaction.

Question 24

steps to balance acidic equations

Answer 24

1. split into two equations
2. balance main equation elements
3. add H2O and H+ to balance the O and H
4. add e^- to balance charges
5. distribute opposite charge to respected equations.
6. combine equations.

Question 25

steps to balance basic equations

Answer 25

1.split equations
2. redox numbers filled
3. balance main equation elements
4. add H2O and H+ to balance O and H
5. add OH^- to balance the H+ to make H2O
6. find charges and balance e^-
7. distribute to make e^- equal for both equations
8. if you have H2O on both sides of equation simplify
9. combine equations

Question 26

mass number

Answer 26

number of protons and neutrons together

Question 27

atomic number

Answer 27

number of protons

Question 28

isotopes

Answer 28

atoms of the same element have different mss due to different numbers of neutrons in those atoms

Question 29

alpha decay

Answer 29

is the loss an alpha particle 4/2He

Question 30

beta decay

Answer 30

the loss of a beta particle 0/-1e

Question 31

gamma radiation

Answer 31

is the loss of a gamma ray which is high energy radiation that almost always accompanies the loss of a nuclear particle 0/0Gamma

Question 32

positron emission

Answer 32

some nuclei decay by emitting a positron, a particle that has the same mass as but an opposite charge to that of an electron. 0/1e

Question 33

electron capture

Answer 33

an electron from the surrounding electron cloud is absorbed into the nucleus. 0/-1e

Question 34

belt of stability

Answer 34

shows which nuclides would be stable

Question 35

particle accelerators

Answer 35

(atom smashers) are enormous using strong magnetic and electric fields to make the particles move so fast

Question 36

linear accelerator

Answer 36

has tubes of variable lengths and charges to make the particle move faster

Question 37

cyclotron

Answer 37

uses D-shaped magnets to keep particle moving in a spiral

Question 38

synchrotron

Answer 38

accelerates particles in a path, which is circular.

Question 39

carbon dating

Answer 39

the half life of C-14 is 5730 years.

Question 40

Becquerel (Bq)

Answer 40

one nuclear disintegration per second

Question 41

Curie (Ci)

Answer 41

defined as 3.7X10^10 disintegrations per second. This is the rate of decay of 1g of radium.

Question 42

Film Badges

Answer 42

radioactivity was first discovered by Henri Becquerel because it fogged up a photographic plate

Question 43

Geiger counter

Answer 43

measure the amount of activity present in a radioactive sample.

Question 44

phosphors

Answer 44

some substances absorb radioactivity and emit light.

Question 45

radio tracers

Answer 45

are radioisotopes used to study a chemical reaction.

Question 46

medical application of radiotracers

Answer 46

are administered to a patient and followed certain elements collect more in certain tissues, so an organ or tissue type can be studied based on where the radioactivity collects.

Question 47

Positron emission tomography (PET)

Answer 47

a compound labeled with a position emitter is injected into a patient. blood flow, oxygen and glucose metabolism, and other biological functions can be studied.

Question 48

mass defect

Answer 48

mass differenece

Question 49

nuclear binding energy

Answer 49

energy needed to separate a nucleus into its nucleons

Question 50

fission

Answer 50

heavy nuclei gain stability and give off energy when they split into two smaller nuclei

Question 51

fusion

Answer 51

lighter nuclei emit great amounts of energy by being combined in fusion

Question 52

thermonuclear reactions

Answer 52

reactions that occur on the sun

Question 53

outside the body

Answer 53

gamma rays are most dangerous

Question 54

inside the body

Answer 54

alpha radiation can cause most harm

Question 55

Gray

Answer 55

Gy; absorption of 1 J of energy per kg of tissue

Question 56

rad

Answer 56

for radiation absorbed dose; absorption of 0.01 j of energy per kg of tissue (100rad=1Gy)

Question 57

Relative biological effectiveness RBE

Answer 57

is used to show how much biological effect there is

Question 58

rem

Answer 58

the effective dose # of rem=(#of rad)(RBE)