nuclear chemistry...

Nuclear Chemistry Worksheet-

Show “K-U-E-S” where necessary, otherwise answer completely. Work that does not fit in the provided space needs to be completed on your own paper.

Part A: Completing Nuclear Decay Reactions: 1-10

For each of the atoms listed below, complete the decay reaction by solving for XAZ or other missing information.

Remember that the mass and protons on each side of the arrow need to equal each other.

Part B: Writing Nuclear Decay Reactions:Write equations for the following nuclear decay reactions. Make sure that both mass numbers and atomic numbers are balanced on each side

11. Decay of polonium-218 by alpha (α) emission.

12. Decay of carbon-14 by beta (β-) emission.

13. The alpha decay of radon-198

14. The beta (β-) decay of uranium-237

XHeLa

XHeHo

XeB

XHeNp

XeAm

AZ

AZ

AZ

AZ

AZZ

+→

+→

+→

+→

+→

−

−

42

14857

42

15167

01

135

42

17593

01

247

PoeX

XeAu

XeHe

HeFrX

XHeLr

ZAZ

AZ

AZ

AZ

AZ

21301

01

21179

01

62

42

21187

42

256103

++

+→

+→

+→

+→

−

−

−



Part C: Half-Life:15. If 100.0 g of carbon-14 decays until only 25.0 g of carbon is left after 11 460 years, what is the half-life of carbon-14?

n (number of half-lives) = 2 half-livest½ (half-life of carbon-14) = 5730 yr

16. Thallium-208 has a half-life of 3.053 min. How long will it take for 120.0g to decay to 7.50 g?

n (number of half-lives) = 4 half-livestT(total time) = 12.21 min

17. Gold-198 has a half-life of 2.7 days. How much of a 96g sample of gold-198 will be left after 8.1 days?

n (number of half-lives) = 3 half-livesmr(mass remaining) = 1/8

mf (final mass) = 12g

Part D: Process & Applications of Nuclear Energy:

18. What is the difference between nuclear fusion and nuclear fission?

19. Name three uses for nuclear reactions

20. Describe 2 uses of radioactive tracers.



SolutionsPart A.

Part B:11. Decay of polonium-218 by alpha (α) emission.

PbHePo 21482

42

21884 +→

12. Decay of carbon-14 by beta (β-) emission.

NeC 147

01

146 +→ −

13. The alpha decay of radon-198

PoHeRn 19484

42

19886 +→

14. The beta (b-) decay of uranium-237

NpeU 23793

01

23792 +→ −

PoeBi

HgeAu

LieHe

HeFrAc

MdHeLr

21384

01

21383

21180

01

21179

63

01

62

42

21187

21589

252101

42

256103

++

+→

+→

+→

+→

−

−

−

CsHeLa

TbHeHo

CeB

PaHeNp

CmeAm

14455

42

14857

14765

42

15167

136

01

135

17191

42

17593

24796

01

24795

+→

+→

+→

+→

+→

−

−



Part C:

15. If 100.0 g of carbon-14 decays until only 25.0 g of carbon is left after 11 460 years, what is the half-life of carbon-14?

mf = 25.0g remaining

gg

mm

i

f

41

0.1000.25 ==

mi = 100.0g =

41

how many 21

’s (half-lives)

tT = 11460yr (1/2) (1/2) = 2 half-lives = n

t½

= ? (half-life) t½ =

211460y

= 5730 yrs

n = ? (# of half-lives)n (number of half-lives) = 2 half-lives

t½ (half-life of carbon-14) = 5730 yr

16. Thallium-208 has a half-life of 3.053 min. How long will it take for 120.0g to decay to 7.50 g?

mf = 7.50g remaining

gg

mm

i

f

161

0.1200.75 ==

mi = 120.0g =

161

how many 21

’s (half-lives)

tT = ? (1/2) (1/2)(1/2)(1/2) = 4 half-lives = n

t½

= 3/053 min tT = (3.053 min) 4 = 12.21min

n = ?n (number of half-lives) = 4 half-lives

tT(total time) = 12.21 min



17. Gold-198 has a half-life of 2.7 days. How much of a 96g sample of gold-198 will be left after 8.1 days?

mf = ?3

7.21.8

1/2

==daysdays

ttT

half-lives =n

mi = 96g 3 half-lives = how much remaining

tT = 8.1 days 3 half-lives = (1/2)(1/2)(1/2) = 1/8 remaining

t½

= 2.7 days 96g 81

= 12 g or

n = ? 296g

= g48 1st half-life

248g

= g24

224g

= 12gn (number of half-lives) = 3 half-lives

mr(mass remaining) = 1/8

mf (final mass) = 12g

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