chem test

Question 1

the repulsion between like charged particles

Answer 1

electromagnetic force

Question 2

two protons and two neutrons bound together

Answer 2

alpha particle

Question 3

the number of neutrons compared to protons that a nuclide has

Answer 3

neutron to proton ratio

Question 4

the time it takes for half of a radioactive sample to decay

Answer 4

half-life

Question 5

radiating which can remove electrons from atoms and molecules

Answer 5

ionizing radiation

Question 6

the result of a fission reaction

Answer 6

daughter nuclei

Question 7

the ability of radiation to pass through solid material

Answer 7

penetration power

Question 8

radiation which comes from the stars and the sun

Answer 8

cosmic radiation

Question 9

high energy electromagnetic waves

Answer 9

gamma-ray

Question 10

radioactive decay into a different isotope

Answer 10

transmutation

Question 11

the process of a heavy nucleus splitting into two or more lighter nuclei

Answer 11

fission

Question 12

radiation which can be found throughout nature

Answer 12

terrestrial radiation

Question 13

a neutron that has been converted into a proton, an electron, and a neutrino

Answer 13

beta particle

Question 14

when two nuclei become one, heavier nucleus

Answer 14

fusion

Question 15

the creation of a new nucleus

Answer 15

nucleogenesis

Question 16

in which type of nuclear decay does the atomic number remain the same

Answer 16

gamma decay

Question 17

radioactivity which is in the form of high energy waves is known as

Answer 17

gamma decay

Question 18

when a radioisotope changes from element to another it is called

Answer 18

transmutation

Question 19

Tritium (^3H) undergoes beta decay. the element which is produced is

Answer 19

helium

Question 20

nuclear power-plants work on the basis of

Answer 20

nuclear fission

Question 21

which of the following is not true of the nuclear strong force

Answer 21

it is weaker than the electromagnetic force

Question 22

the two elements formed in the big bang nucleosynthesis were

Answer 22

hydrogen and helium

Question 23

the ratio of elements found after the big bang was

Answer 23

75% hydrogen and 25% helium

Question 24

what conditions are required for nuclear fusion

Answer 24

extreme temperature and pressure

Question 25

after three half-lives, how much of radioactive sample will remain

Answer 25

12.5%

Question 26

when sodium-24 decays it does so by beta emission, gamma radiation is also released. write the equation for the decay of sodium-24 by beta emission.

Answer 26

2411Na –> 2412Mg+01e

Question 27

define the term half-life as it applies to sodium-24

Answer 27

it takes 15 hours for half of a sample of sodium-24 to decay into Magnesium-24

Question 28

a sample of sodium-24 with a mass of 20g undergoes radioactive decay. calculate the amount of sodium left after 60 hours give your answer as a percentage.

Answer 28

60/15= 4 half lives
(1/2)^4 x 20=1.25g
6.25%

Question 29

there are 21 recognized isotopes of sodium, with ass numbers ranging from 18-39. only one of these, sodium-23 is stable. explain why sodium-23 is stable in terms of: it’s neutron to proton ration and the band of stability

Answer 29

sodium-23 has a ratio of 11:12. it’s close to a ratio of 1:1. it fits into the band of stability.

Question 30

there are 21 recognized isotopes of sodium, with ass numbers ranging from 18-39. only one of these, sodium-23 is stable. explain why sodium-23 is stable in terms of: the forces operating in its nucleus

Answer 30

the strong nuclear force works against the repulsion to make it stable

Question 31

sodium-24 is used in diagnostic medicine as a tracer to detect blood clots: what is a tracer

Answer 31

a tracer, a radioactive element, is used to find issues in the body through imaging

Question 32

sodium-24 is used in diagnostic medicine as a tracer to detect blood clots: how does a tracer work?

Answer 32

tracers are inserted through ivs or injected when inside the body. tracers emits particles that can be imaged (via PET scans)

Question 33

sodium-24 is used in diagnostic medicine as a tracer to detect blood clots: describe the application of another named radioisotope which is used in either medicine or industry

Answer 33

carbon-14: how old something is

Question 34

describe the process of nuclear fusion

Answer 34

nuclear fusion is the process of two smaller nuclei joining or fusing together to form a heavier nucleus

Question 35

where does this process of nuclear fusion occur

Answer 35

stars/sun

Question 36

explain why nuclear fusion requires extreme temperature and pressure

Answer 36

this reaction requires extreme temperature and pressure to overcome the electrostatic or repulsion forces.

Question 37

nucleosynthesis occurred in the big bang to form the first nuclei. describe this process and name the two nuclei that were initially formed as part of this process

Answer 37

the process of creating new nuclei from existing protons and neutrons like helium and hydrogen

Question 38

explain how nuclear fission differs to nuclear fusion. include the equation for the nuclear fission of uranium

Answer 38

fission splits them apart and needs a neutron. fusion puts them together and needs high heat and pressure.

Question 39

if it is in the sun then its

Answer 39

nuclear fusion

Question 40

the first elements were formed by

Answer 40

the big bang nucleosynthesis

Question 41

alpha reduces atomic number by

Answer 41

2

Question 42

repulsion is greater than nuclear force than it is

Answer 42

unstable