nuclear chemistry workpacket

Nuclear Chemistry or Radiochemistrv -Know basic vocabulary -2 types of transmutations -4 nuclear decay emissions -Write ...

0 downloads 177 Views 791KB Size
Nuclear Chemistry or Radiochemistrv -Know basic vocabulary -2 types of transmutations -4 nuclear decay emissions -Write nuclear decay reactions -Calculate y^ lives -know how nuclear powerplants work -Know about Chernobyl -Be able to complete the U-238 decay series Vocabulary Terms Mass defect Transmutation Binding energy Half-life Fission Fusion Alpha particle Beta particle Positron Radioactive decay Gamma rays Geiger counter Radioisotope Band of stability Nucleon Nuclide Ionizing radiation Chain reaction Radiotracer

Responses

Definitions The difference between the actual mass of an atom and the sum of the masses of the isolated particles composing it The conversion of one element into another; may be natural or artificial The energy required to split the nucleus into separate nucleons The length of time necessary for one-half an amount of a radioactive nuclide to disintegrate The splitting of an atomic nucleus into smaller fragments, accompanied by the release of neutrons and a large amount of energy A nuclear reaction in which small nuclei are combined to make a larger nucleus, accompanied by the release of a large amount of energy A helium nucleus, containing two protons and two neutrons A fast moving electron emitted from certain radioactive nuclei; it is formed when a neutron decomposes A particle that has the same mass as an electron but has a positive charge The process in which an unstable nucleus loses energy by emitting radiation A quantum of energy of very high frequency and very short wavelength A gas-filled metal tube used to detect the presence of beta radiation Isotopes that have unstable nuclei and undergo radioactive decay The location of stable nuclei on a neutron-vs.-proton plot A particle found in the nucleus of an atom; a proton or a neutron An atom of a specific energy with a specified number of protons and a specified number of neutrons in its nucleus Radiation which has enough energy to produce ions by knocking electrons off some of the atoms it strikes A self-sustaining fission process caused by the production of neutrons that proceed to split other nuclei A radioactive nuclide, introduced into an organism for diagnostic purposes, whose pathway can be traced by monitoring its radioactivity

Nuclides (I) Nuclide Helium-4

Atomic#

#Protons

#Electrons

#Neutrons

2 14

Carbon Boron - 11

Mass#

5 29

Silicon -

15

Copper -63 42

Arsenic -75 Bromine -

79

Gold -197

86

Radon-222 238

Uranium Neon-22

45

80

146

10 35

Copper - 64 Lithium-

6

3

Hyphen notation

Nuclear notation

i^jl

Name

Types of Nuclear Decay . . . A nuclear reaction is a reaction that affects the

^'^

^

of an atom.

. . . A transmutation is a change in the identity of a nucleus as a result of a change in the number of its

.

. . . Radioactive decay is the spontaneous disintegration of a nucleus into a slightly lighter nucleus, accompanied by emission of

,

, or both.

Nuclear change or decay is an process. The stability of a nuclide partly depends on the relative number of and it contains. In some cases, having too many neutrons is the cause of the . Stable nuclides are recognized experimentally because they do not change. Unstable nuclides in order to reach stability. Changing to a stable nuclide may involve one or more decays. In nuclear decay, the initial nucleus is called the , and the nev^ nucleus that results is called the . Nuclear equations representing a nuclear reaction are balanced when the sum of the atomic numbers on the right is equal to the on the left. Sums of the numbers on the right and left sides must be equal also. Nuclear Decay Organizer and Nuclear Equation Practice Alpha Particle Emission Symbol

Beta Particle Emission

2He or |a

How It changes the nucleus...

>

Gamma Ray Emission

Positron Particle Emission

or_?^

.IP

...Decreases the mass number by 4

. . .Converts a neutron into a proton

. . .Converts a proton into a neutron.

. . . Decreases the atomic # by 2

. . .Increases atomic # by 1

. . . Atomic # decreases by 1; mass # stays same

. . .No change to the nucleus

Examples of Nuclear Decay Processes

p

a emission ^llU

tHe

+

p * emission

emission

^tTh

1.

\Nr\te an equation to represent the decay of radium-226 by a emission and bismuth-209 by 3^ emission.

2.

The products from a nuclear reaction are an a particle and polonium-218. Identify the parent nuclide and write equation.

3.

Write equations for the decay of and radium-224 by a emission.

4.

Write equations for the decay of cobalt-60 and calcium-39 by P emission.

5.

Write an equation for the decay of copper-64 and nitrogen-12 by p'^emission.

6.

Fill in the correct symbol to complete each equation. a) ^^2U ^ c)

'llRa

?

+2^6

-> 'llRn

b) mm +

?

d) f.K

^ ^

?

_?e

t|]Ca + ?

7.

Write an equation for the decay of polonium-218 by a emission.

8.

Write an equation for the decay of carbon-14 by p" emission. Then by P * emission.

Table O

Symbols Used in Nuclear Chemistry Notation

Symbol

alpha particle

l l i e or | a

a

beta particle

_','<•

r

Name

gamma radiation

?,Y

neutron proton positron

Y n

|TI <>,- {p

P 1^"

Name

Per

Nuclear Decay

Using a periodic table, fill in the blanks to complete the following nuclear equations. Then, identify which type(s) of decay particles were produced.

Standard: Students know the three most common forms of radioactive decay (alpha, beta, and gamma) and know how the nucleus changes in each type of decay.

Describe the change that took place above.

Describe the change that took place above.

Describe the change that took place above.

6 ^

^

+

7iV

Describe the change that took place above.

Describe the change that took place above.

Describe the change that took place above.

Describe the change that took place above.

'i'c

+ ; / /

^

+

Describe the change that took place above.

„ V

CD 05 >

<

CD

£ £

CD

Nuclear Chemistry Worksheet Using your knowledge of nuclear chemistry, write the equations processes:

for the following

1)

The alpha decay of radon-198

2)

The beta decay of uranium-237

3)

Positron emission from silicon-26

4)

Sodium-22 undergoes electron capture

5)

What is the difference between nuclear fusion and nuclear fission?

6)

What is a "mass defect" and why is it important?

7)

Name three uses for nuclear reactions.

For chemistry help, visit www. chem fiesta, com

©2003 Cavalcade Publishing-

All Rights

Reserved

Nuclear Chemistry Worksheet - Solutions Using your knowledge processes:

of nuclear chemistry, write the equations

for the following

1)

The alpha decay of radon-198

2)

The beta decay of uranium -237

3)

Positron emission from silicon-26

4)

Sodium-22 undergoes electron capture

5)

What is the difference between nuclear fusion and nuclear fission? In nuclear fusion, small nuclei are combined to form a larger nucleus " this process releases a very large amount of energy, and is the main source of energy in the sun. In nuclear fission, large nuclei break apart to form smaller ones, releasing a large amount of energy. Fission is used in nuclear power plants to generate energy.

6)

What is a "mass defect" and why is it important? "Mass defect" refers to the difference between the mass of the nucleons (protons + neutrons) in a nucleus when weighed separately and the mass of the nucleus when it's put together. This difference is important because this missing mass is converted to energy using E=mc^ that's used to hold the nucleus together.

7)

Name three uses for nuclear reactions. • • •

Nuclear weapons Medicine Nuclear power generation

For chemistry help, visit www. chemfiesta. com

©2003 Cavalcade Publishing-

All Rights

Reserved

Name

pd

2009

Half-Life In a sample of radioactive nuclides, the decay of an individual nuclide is a

event. It is impossible to predict which

nucleus will be the next one to undergo a nuclear change. How, then, do you make sense out of things that cannot be predicted on an individual basis? One approach is to predict change for a given amount of a very large number of nuclei —for example, one half. Scientists commonly discuss radioactive decay in terms of half-life. The

it tal
radioactive sample to decay is known as its half-life. The half-life of fluorine-21 is approximately five seconds. If a sample of fluorine-21 contains one million atoms, then 500 000 of the nuclei will decay within five seconds. Within another five seconds, 250 000 additional nuclei (one half of those remaining) will decay, and so on. Many radioactive nuclei have much longer half-lives. A sample of one million nuclei of strontium-90 will decay much more slowly because the half-life of strontium-90 is about 29 years. Half -lives may be used calculate the fraction of parent nuclides that remain after a certain amount of time. Helpful Hints!! (Use your y" button or x^); n = total time / Vz life time; n = # of >i lives that have occurred; mass remaining = mass x Vz

Sample calculation: Fluorine-21 has a half-life of approximately 5 seconds. What fraction of the original nuclei would remain after 1 minute? If you began with 42 grams of fluorine, how many grams of fluorine would remain?

9.

lodine-131 has a half-life of 8 days. What fraction of the original sample would remain at the end of 32 days?

10. The half-life of chromium-51 is 28 days. If a sample contained 510 grams, how much chromium would remain after 56 days? How much would remain after 1 year?

11.

The half-life of iodine-125 is 60 days. What fraction of iiodine-125 would be left after 350 days?

12. Titanium-51 decays by P " emission with a half-life of 6 minutes. What fraction of titanium would remain after 1 h?

13. A medical institution requests 1 gram of bismuth-214, which has a half-life of 20 min. How many grams of bismuth-214 must be prepared and shipped, if the shipping time is exactly 2 h?

14. What fraction of radioactive strontium-90, formed in the last atmospheric nuclear-bomb test in 1963, will be present in the environment in the year 2050? The half-life of strontium-90 is 29 years?

15. The half-life of phosphorus-30 is 2.5 min. What fraction of phosphorus-30 would remain after 10 min?

16. Chromium-48 decays by P^emission. After 6 half-lives, what fraction of the original nuclei would remain?

Name WS Half-life 2 The Half-Life of Radon-226 is approximately 4 days. On the grid below, plot the amount of Radon-226 left after each 4 day time period when you start with a 48g sample of Radon-226 1

-4

i

"i

\

i

\

j

1

i 1 i

••\ ! 1

:

. j

.. . ;

i

\

•4

..1 4 j

i 1

i

1

!

1

;

1

i

i 1 1

1 1 j

1

!

1 r :

1 .

1

\

;

.

:

:

Questions 1. 2. 3. 4. 5.

How many grams of radon would be present after How many grams of radon would be present after How many grams of radon would be present after I f 8 g of radon are left, what is the time elapsed? How many grams of radon would be present after

4 days? 12 days? 24 days? 6 days?

.

1

:

i

i

;

i

i

1

WS Decay Series of U-238

Name 1.

Complete the table using the decay series of U-238

238

3 CO

^0?

81

92 atomic number

2. Complete the reactions and mark the graph above with the nuclide that is formed.

238 U 92

238 u 92

234 Th 90

a

234

6

Pa

234 u 92

6

a

218 Po 84

a

a

222 Rn 86

a

226 Ra 88

230 th 90

a 214 82Pb

214 B i 83

214 Po 84

6

a

210 Pb 82 6

stable ^^^Pb 82

a

210 Po 84

83

Table N

Table K

Common Acids

Selected Radioisotopes

Name

Formula

Nuclide

HCl(aq)

hydrochloric acid

HN02(aq)

nitrous acid

HN03(aq)

nitric acid

H2S03(aq)

sulfurous acid

HgSO^lati)

sulfuric acid

H3P04(aq)

phosphoric acid

H2C03(aq) or C02(aq)

carbonic acid

Half-Life 2.695 d

14c

5715 y

-Ca

182 ms 5.271 y 30.2 y

13'CS

ethanoic acid

22UF,

27.4 s

1.23 s

Table L

10.73

NaOH(aq)

sodium hydroxide

KOH(aq)

potassium hydroxide

Ca(OH)2(aq)

calcium hydroxide

NH3(aq)

aqueous ammonia

Common Acid-Base Indicators Indicator

Color Change

methyl orange

3.1-4.4

red to yellow

bromthymol blue

6.0-7.6

yellow to blue

phenolphthalein

8-9

colorless to pink

litmus

4.5-8.3

red to blue

bromcresol green

3.8-5.4

vellow to blue

thymol blue

8.0-9.6

yellow to blue

Source: The Merck Index, 14'^ ed., 2006, Merck Publishing Group

Reference Tables for Physical Setting/Chemistry - 2011 Edition

gold-198 carbon-14

r

p-

cobalt-60 cesium-137 iron-53

a

francium-220

r r

hydrogen-3 iodine-131 potassium-37 potassium-42

r

kiypton-85

(3-

nitrogen-16

l9Ne

17.22 s

(3^

neon-19

32p

14.28 d

|3-

phosphorus-32

10^ y

a

plutonium-239

1599 y

a

radium-226

3.823 d

a

radon-222

239p^

2.410

X

90s,

2.13

Table M

Approximate pH Range for Color Change

7.13 s

16^1

Name

V

Nuclide Name

calcium-37

12.36 h

42K

Formula

V

8.021 d

1311

(acetic acid)

Common Bases

r

8.51 min 12.31

CH3COOH(aq) or HC2H302(aq)

Decay Mode

X

29.1 y

P-

strontium-90

lO^y

(3-

technetium-99

10^0 y

a

thorium-232

X

10\

a

uranium-233

7.04

X

10''^ y

a

uranium-235

4.47

X

lO'^ y

a

uranium-238

232Th

1.40

233u

1.592

235u 2 3 S u

X

Source: CRC Handbook of Chemistry and Physics, CRC Press

91^* ed., 2010-2011,