Practice problems week 2 PDF

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Study Session 2 1) The atomic number (Z) is equal to A) the number of the protons. B) the sum of the number of the neutrons and electrons. C) the sum of the number of protons, neutrons, and electrons. D) the sum of the number of protons and neutrons. 2) What element does "X" represent in the following symbol? Can also be represented as X-80, but you need the 35 to know where to look it up on the periodic table X

3) What element does "X" represent in the following symbol? X

4) Determine the number of protons, neutrons, and electrons in the following: X

5) Determine the number of protons, neutrons, and electrons in the following: X

6) What element is defined by the following information? p+ = 17

n° = 20

e- = 17

7) The number of nucleons in a

Co nucleus is

1

8) Which of the following statements about isotopes is TRUE? A) Isotopes of the same element differ only in the number of electrons they contain. B) An isotope of an atom with a larger number of neutrons is larger than an isotope of the same atom that contains fewer neutrons. C) Isotopes of the same element have the same mass. D) Isotopes of the same element don't usually have the same properties. E) Some elements have 3 or more naturally occurring isotopes. 9) Identify the scientist(s) that were awarded the Nobel Prize in physics for the discovery of radioactivity in 1903. You can look it up for now but when you have time Watch this great movie (optional)! https://youtu.be/wbuDmY5gpXQ A) Johannes Geiger, Marie Curie B) Albert Einstein C) Antoine-Henri Becquerel, Marie Curie, Pierre Curie D) Ernest Rutherford, Johannes Geiger E) Galileo Galilei 10) Identify the elements discovered by Marie Curie. A) polonium and radium B) radium and cesium C) argon and xenon D) radon and xenon E) selenium and tungsten

Study Session 3 11) Write the symbol for an alpha particle.

12) Write the symbol for a beta particle.

13) Write the symbol for a gamma particle.

14) Write the symbol for a positron. 2

15) Describe what changes occur during beta decay. A) The mass number and atomic number decrease. B) The mass number and atomic number increase. C) The mass number increases and the atomic number is unchanged. D) The mass number is unchanged and the atomic number increases. E) The mass number and atomic number do not change. 16) Describe what changes occur during gamma ray emission. A) The mass number and atomic number decrease. B) The mass number and atomic number increase. C) The mass number is unchanged and the atomic number decreases. D) The mass number increases and the atomic number decreases. E) The mass number and atomic number do not change. 17) Describe what changes occur during positron emission. A) The mass number and atomic number decrease. B) The mass number and atomic number increase. C) The mass number is unchanged and the atomic number decreases. D) The mass number decreases and the atomic number is unchanged. E) The mass number and atomic number do not change. 18) Describe what changes occur during electron capture. A) The mass number and atomic number decrease. B) The mass number and atomic number increase. C) The mass number is unchanged and the atomic number decreases. D) The mass number decreases and the atomic number is unchanged. E) The mass number and atomic number do not change. 19) The following reaction represents what nuclear process? Am 

He +

Np

A) beta emission B) alpha capture C) alpha emission D) electron capture E) positron capture

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20) The following reaction represents what nuclear process? Cs +

e 

Xe

21) The following reaction represents what nuclear process? Pb 

e+

Bi

22) Write a nuclear equation for the alpha decay of

Am.

23) Write a nuclear equation for the alpha decay of

Pu.

24) Determine the identity of the daughter nuclide from the positron emission of

C.

25) Determine the identity of the daughter nuclide from the electron capture by

Rb.

26) Determine the identity of the daughter nuclide from the beta decay of

P.

27) Determine the identity of the daughter nuclide from the positron emission of

F.

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Study Session 4 28) Which of the following nuclides are most likely to decay via beta decay? (consult the Valley of Stability table and assess the Neutron/Proton Ratio to determine if the stability will increase by losing a proton or a neutron) Iodine-131 Argon-40 Lead-206

29) Which of the following nuclides are most likely to decay via positron emission? Cs-137 Al-24 K-42

30) Define mass defect. A) the difference in mass between an atom and the sum of its separate components B) an atom with too many neutrons C) the difference in mass between a radioactive atom and a nonradioactive atom D) energy released in a radioactive reaction E) energy absorbed in a radioactive reaction

31) Calculate the mass defect in Fe-56 if the mass of an Fe-56 nucleus is 55.921 amu. The mass of a proton is 1.00728 amu and the mass of a neutron is 1.008665 amu.

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The following energy unit conversions may be used when solving for E = mc2 speed of light = 3.0 x 108 m/s, 1 amu = 1.6606 x 10-24 g, 1 Joule = kg m2/s2, 1 Joule = 6.242 x 1012 MeV, for nuclear binding 1 amu = 931 MeV

32) Determine the binding energy of an O-16 nucleus. The O-16 nucleus has a mass of 15.9905 amu. A proton has a mass of 1.00728 amu, a neutron has a mass of 1.008665 amu. Consult the Lesson to find conversions between energy and mass units and energy to energy units A) 8.84 MeV B) 128 MeV C) 138 MeV D) 78.1 MeV E) 38.2 MeV

33) Determine the binding energy of an F-19 nucleus. The F-19 nucleus has a mass of 18.99840325 amu. A proton has a mass of 1.00728 amu, a neutron has a mass of 1.008665 amu, (for this problem, make a direct relationship between atomic mass units and Mega Electron volts) 1 amu is equivalent to 931 MeV of energy. Consider using a more straightforward relationship for nuclear binding; 1 amu = 931 MeV

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34) Identify the nuclide that has the longest half-life. A) B)

U C

C)

Rn

D)

Th

E)

Th

35) Fluorine-18 undergoes positron emission with a half-life of 1.10 × 102 minutes. If a patient is given a 248 mg dose for a PET scan, how long will it take for the amount of fluorine-18 to drop to 83 mg? (Assume that none of the fluorine is excreted from the body.)

36) The age of an ancient tree trunk is estimated using radiocarbon dating. If the trunk has a C14 decay rate that is 34% of what it is in living plants, how old is the trunk? The half-life of C-14 is 5730 years.

37) Neptunium-239 has a half-life of 2.35 days. How many days must elapse for a sample of 239Np to decay to 0.100% of its original quantity?

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38) What percentage of a radioactive substance remains after 6.00 half-lives have elapsed? another common equation used to solve a problem like this is Fraction Remaining = (0.5)number of half-lives (x 100% to change fraction to %)

39) Strontium-90 is a byproduct in nuclear reactors fueled by the radioisotope uranium-235. The half-life of strontium-90 is 28.8 yr. What percentage of a strontium-90 sample remains after 75.0 yr?

40) Determine the half-life of a nuclide that loses 38.0% of its mass in 407 hours.

Study Session 5 CHALLENGE PROBLEM (just for fun, not graded) A geological sample is found to have a Pb-206/U-238 mass ratio of 0.337/1.00. Assuming there was no Pb-206 present when the sample was formed, how old is it? The half-life of U-238 is 4.5 × 109 years. (A mass ratio is not the same as a number of atoms ratio if the elements being ratioed are not identical) Answer = 2.1 × 109 years

41) The splitting of a heavy nucleus to form two or more lighter ones is called A) radioactive cleavage. B) nuclear fission. C) nuclear fusion. D) radioactive merge. E) half-life.

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42) Define transmutation. A) the transformation of one element into another B) the loss of neutrons from an atom C) the loss of electrons from an atom D) the loss of protons from an atom E) the gain of neutrons to an atom

43) Identify the missing particle in the following nuclear equation: H+

H 

He + ? +

J

44) Identify the missing particle in the following nuclear equation: U 

Sr + ? + 2

n+4

J

45) Write a nuclear equation to describe the spontaneous fission of

Am to form I-134 and

Mo-107. Determine how many neutrons are produced in the reaction.

46) Write a nuclear equation to describe the neutron induced fission of U-235 to form Xe-134 and Sr-100. Determine how many neutrons are produced in the reaction. (remember to include the initial neutron that got the reaction started on the reactants side of equation)

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47.) In your lab notebook (Lab 2) set up the following calculation

Half-life of Ba-137m = t1/2 =

. 

You will be calculating the half-life for the barium experiment. You have information for time and for the cpm (adjusted for the background radiation) To find the half-life (t1/2), you will need to solve for the constant ‘k’ and plug it into the above equation. You will find k as the slope of a straight line from your data a. Graph Time as a function of CPM and see that it is a curved line b. Taking the natural log of both sides of the following equation (which represents the curved trend) you get a formula that is in the y= mx + b form cpm = e-k(time) ln(cpm) = -k(time) y = m x + 0 c. Make two new columns in your spreadsheet and graph the straight line. What is the slope of the line? x-axis Time y-axis Ln(cpm)

48.) Now that you have k, determine the half-life of Barium-137m

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49.) For the next set of data, you want to find how many sheets of lead it takes to completely block the gamma radiation. *You must change the x-axis (Number of lead sheets x 1.20 mm = thickness of lead)

If you graphed the data you would see that the curve follows the equation Curved line: cpm = e-k(number of lead sheets) Straight line: Ln(cpm) = -k(number of lead sheets) Straight line: Ln(cpm) = -k(lead thickness) Form: y = m x

+b

Make two new columns in your spreadsheet for the Cobalt-60 experiment and fill in the data with Excel formulas x-axis  Lead Thickness (mm) (multiply the number of lead sheets by its thickness of 1.20 mm/sheet) y-axis Ln(cpm)

a. Graph Ln(cpm) as a function of Lead Thickness and place the equation on the graph (do not set the intercept to zero.) b. Looking at the graph you may notice that when y = 0, the trendline will cross the x-axis and show you the lead thickness that allows zero counts per minute of radiation. In other words, how thick (in mm) does lead have to be to completely block this radiation? c. Using the equation from the trendline, set y=0 and solve for x. This will tell you the thickness of lead required to block gamma radiation

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50.) You will repeat the procedure from above for the Strontium-90 data set to determine the thickness of Aluminum required to block beta emission radiation. x-axis  Aluminum Thickness (mm) (multiply the number of Al sheets by its thickness of 0.03 mm/sheet) y-axis Ln(cpm) Using the equation from the trendline, set y=0 and solve for x. This will tell you the thickness of aluminum required to block beta radiation x

These calculations should appear in your lab notebook and on this practice problem set.

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