January 2023

28 When the nucleus of an atom of neon-19 decays, which particle is emitted?

**Solution:**

Table N on the Reference Table shows different isotopes with their decay modes. The decay mode for Ne-19 is **β+ (positron) or e+.**

**Answer: **4

29 Which nuclear emission has the greatest mass?

(1) positron

(2) gamma ray

(3) beta particle

(4) alpha particle

**Solution:** Table O on the Reference Table lists all of the nuclear isotopes symbols. On top of the symbol is the mass number. Alpha particle has the highest mass number.

Answer: 4

30 Which statement describes the net change that occurs during nuclear fission?

(1) Electrons are converted to protons.

(2) Protons are converted to electrons.

(3) Mass is converted to energy.

(4) Energy is converted to mass.

**Solution: **During nuclear fission, a small amount of mass is converted into a large amount of energy.

**Answer:** Choice 3 is the correct answer choice.

48 Given the equation representing a reaction:

This equation represents

(1) sublimation

(2) condensation

(3) fission

(4) fusion

**Solution:** Sublimation is a phase change going from solid to gas phase. Condensation is a phase change going form gas to liquid. Fission is a nuclear reaction. In fission we see neutron on the left side. Fusion is a nuclear reaction with small nuclei coming together such as hydrogens coming together to form larger atoms.

**Answer:** This reaction is fusion, choice 4

August 2022

28 Which symbol represents a nuclear emission with the greatest mass and the greatest ionizing power?

1. α

2. β+

3. β-

4. y

**Explanation:** We can take a look at the Table O on the reference table to see what each symbol means. 1. α = alpha particle 2. β+ = positron 3. β- = beta particle 4. y = gamma radiation. Alpha particle has the greatest mass (4amu) according to the chart (mass number is on the top left corner of the symbol) and the greatest ionizing power.

**Answer:** 1

29 One potential benefit of nuclear fusion reactions is

(1) reactor meltdown

(2) uncontrolled chain reaction

(3) production of large amounts of energy

(4) production of radioactive waste materials

**Explanation:** The question is asking about benefits of nuclear fusion reactions. We can eliminate anything that is not a benefit such as radioactive waste, reactor meltdown and uncontrolled chain reaction. Production of large amount of energy can be used to benefit people to use the energy produced in their homes.

**Answer:** 3

30 Determining the age of a wooden beam from a sunken ship is an example of a beneficial use of

(1) Lewis structures

(2) polyatomic ions

(3) radioactive nuclides

(4) homogeneous mixture

**Explanation:** Radioactive nuclides are used in determining the age of objects and fossils.

**Answer:** 3

June 2022

29 Which emission will be released from an unstable Fe-53 nucleus?

(1) an alpha particle

(2) a beta particle

(3) a positron

(4) a proton

**Explanation:** Table N on the Reference Table shows us the decay mode of different nuclides. Fe-53 has a β+ decay mode. Table O shows the symbol and name of nuclear particles.

Answer:3

30 What is a potential risk associated with radioactive isotopes?

(1) biological exposure

(2) curing of diseases

(3) industrial measurements

(4) tracing chemical processes

**Explanation:** We are looking for a risk; something negative. Curing diseases and tracing chemical processes as well as industrial measurements are all positive.

**Answer:** 1

50 Which net change occurs in both nuclear fission and nuclear fusion reactions?

(1) Mass is converted to energy.

(2) Energy is converted to mass.

(3) Small nuclei form a larger nucleus.

(4) A large nucleus forms smaller nuclei.

**Explanation: **Both nuclear fission and nuclear fusion reactions produce a great deal of energy because they involve mass being converted to energy.

**Answer: **1

January 2020

29 Which radioactive emission has the greatest penetrating power, but the *least *ionizing power?
(1) alpha particle

(2) beta particle

(3) gamma ray

(4) positron

**Solution:** Gamma rays have the greatest penetrating power, but the *least *ionizing power

**Answer:** 3

30 Which statement describes a benefit of using fission reactions?

(1) Radioactive waste must be stored for long periods of time.

(2) Nuclear fuel consists of stable isotopes.

(3) Gamma radiation is produced.

(4) Large amounts of energy are produced per mole of reactant.

**Solution:** A benefit must be something positive. Storing radioactive water and producing gamma radiation are negative, eliminating choices 1 and 3. The reason fission reactions are used is to primarily produce energy.

**Answer:** 4

48 Which emission causes the atomic number of a nuclide to decrease by 2 and its mass number to decrease by 4?

(1) an alpha particle

(2) a beta particle (3) gamma radiation

(4) a positron

**Solution:** The question is asking us which nuclear particle has an atomic number of 2 and mass number of 4. Looking at Table O on the Reference Table, we see that alpha particle has a mass number of 4 and an atomic number of 2.

**Answer:** 1

50 Given two equations representing reactions:

Which type of reaction is represented by each of these equations? (1) Both equations represent fission. (2) Both equations represent fusion. (3) Equation 1 represents fission and equation 2 represents fusion.

(4) Equation 1 represents fusion and equation 2 represents fission.

**Solution:** Let's learn how to recognize a fusion and a fission reaction.

Fusion is a nuclear reaction with small nuclei such as hydrogens coming together to form a nucleus with a greater mass. In a fission reaction, we will see a neutron on the reactant side with another atom.

**Answer:** 3

August 2019

29 In which reaction is an atom of one element converted into an atom of another element? (1) combustion (2) fermentation (3) oxidation-reduction

(4) transmutation

Solution: Transmutation is a reaction where an atom of one element converted into an atom of another element.

Answer: 4

30 In which type of nuclear reaction do nuclei combine to form a nucleus with a greater mass? (1) alpha decay

(2) beta decay

(3) fusion

(4) fission

**Solution:** Fusion is a nuclear reaction with small nuclei coming together such as hydrogens coming together to form a nucleus with a greater mass.

**Answer:** 3

49 Which radioisotope requires long-term storage as the method of disposal, to protect living things from radiation exposure over time?

(1) Pu-239

(2) Fr-220 (3) Fe-53

(4) P-32

**Solution:** We need to take a look at Table N on the Reference Table which lists half lives. The question is asking about long term storage which means we are looking for a radioisotope with a long half life. Pu-239 has a half life of 2.410 × 10^4 years. Fr-220 is 27.4 seconds, Fe-53 is 8.51 minutes , and P-32 is 14.28 days.

**Answer:** 1

June 2019

28 In which type of nuclear reaction do two light nuclei combine to produce a heavier nucleus? (1) positron emission

(2) gamma emission

(3) fission

(4) fusion

**Solution:** Fusion is a nuclear reaction where light nuclei combine to produce a heavier nucleus.

**Answer:** Choice 4

29 Using equal masses of reactants, which statement describes the relative amounts of energy released during a chemical reaction and a nuclear reaction?

(1) The chemical and nuclear reactions release equal amounts of energy.

(2) The nuclear reaction releases half the amount of energy of the chemical reaction.

(3) The chemical reaction releases more energy than the nuclear reaction.

(4) The nuclear reaction releases more energy than the chemical reaction.

**Solution: **Nuclear reactions such as fission and fusion release more energy than chemical reactions.

**Answer:** Choice 4

30 The ratio of the mass of U-238 to the mass of Pb-206 can be used to (1) diagnose thyroid disorders

(2) diagnose kidney function

(3) date geological formations

(4) date once-living things

**Solution:** U-238 is used for figuring out the age of geological formations.

**Answer: **Choice 3

50 Which nuclear equation represents a spontaneous decay?

**Solution:** In a spontaneous decay equation we will see only one reactant on the left side of the equation.

**Answer: **Choice 1

January 2019

29 Compared to the energy released per mole of reactant during chemical reactions, the energy released per mole of reactant during nuclear reactions is (1) much less (2) much greater (3) slightly less (4) slightly greater

**Solution: **Nuclear reactions such as fission and fusion release much more energy than chemical reactions.

**Answer:** 2

30 Which phrase describes a risk of using the radioisotope Co-60 in treating cancer? (1) production of acid rain (2) production of greenhouse gases

(3) increased biological exposure

(4) increased ozone depletion

**Solution: **Co-60 decays by gamma decay. Therefore the risk of using it is increased biological exposure which can cause skin burns, acute radiation sickness, or death.

**Answer:** 3

49 Given the equation:

Which type of nuclear reaction is represented by the equation? (1) fission

(2) fusion (3) beta decay

(4) alpha decay

**Solution:** In a fission reaction, we will see a neutron on the reactant side with another atom. Fusion is a nuclear reaction with small nuclei coming together such as hydrogens coming together to form a nucleus with a greater mass. In beta decay there is a beta particle on the right side (products). In alpha decay, there is an alpha particle on the right side.

**Answer:** 1

50 Which nuclear emission has the *least *penetrating power and the greatest ionizing ability?
(1) alpha particle

(2) beta particle (3) gamma ray

(4) positron

**Solution:** Alpha particle has the *least *penetrating power and the greatest ionizing ability while gamma ray has the greatest penetrating power.

**Answer:** 1

August 2018

27 What evidence indicates that the nuclei of strontium-90 atoms are unstable?

(1) Strontium-90 electrons are in the excited state.

(2) Strontium-90 electrons are in the ground state.

(3) Strontium-90 atoms spontaneously absorb beta particles.

(4) Strontium-90 atoms spontaneously emit beta particles.

**Solution**: Table N on the Reference Table gives decay mode for different radioisotopes. Strontium-90 has a beta decay mode.

**Answer:** 4

28 Which nuclear emission is listed with its notation? (1) gamma radiation, γ

(2) proton, He (3) neutron, β (4) alpha particle, H

**Solution:** Table O on the Reference Table lists nuclear emission particles with their notation.

**Answer:** 1

29 The energy released by a nuclear fusion reaction is produced when (1) energy is converted to mass (2) mass is converted to energy (3) heat is converted to temperature

(4) temperature is converted to heat

**Solution:** In nuclear fusion and fission reactions, a lot of energy is produced from the conversion of mass to energy.

**Answer:** 2

30 Dating once-living organisms is an example of a beneficial use of (1) redox reactions (2) organic isomers (3) radioactive isotopes (4) neutralization reactions

**Solution:** Radioactive isotopes are used dating once-living organisms.

**Answer:** 3

50 Given the equation representing a reaction:

Which type of reaction is represented by this equation?

(1) neutralization

(2) polymerization (3) substitution

(4) transmutation

**Solution: **This is a nuclear equation. We see neutron on the right side. We also see that the identity of the element changes, going from Pb And Zn to Cn. Transmutation is the changing of a nucleus of one element into the nucleus of another element.

**Answer: **4

January 2018

28 In which type of reaction can an atom of one element be converted to an atom of another element? (1) addition

(2) reduction

(3) substitution

(4) transmutation

**Solution:** Transmutation is the changing of a nucleus of one element into the nucleus of another element.

**Answer:** 4

29 An unstable nucleus spontaneously releases a positron. This is an example of (1) radioactive decay (2) nuclear fusion (3) chemical decomposition

(4) thermal conductivity

**Solution:** Radioactive decay is a reaction where an unstable nucleus releases a particle such as position, beta, or alpha.

**Answer:** 1

30 Which phrase describes a risk associated with producing energy in a nuclear power plant?

(1) depletion of atmospheric hydrogen (H2)

(2) depletion of atmospheric carbon dioxide (CO2)

(3) production of wastes needing long-term storage

(4) production of wastes that cool surrounding water supplies

**Solution:** Nuclear power plant produces energy through nuclear reactions. These reactions produce radioactive wastes that could be harmful if released outside. Therefore, there needs to be a long-term storage for the wastes produced.

**Answer:**3

June 2018

27 The stability of an isotope is related to its ratio of (1) neutrons to positrons

(2) neutrons to protons

(3) electrons to positrons

(4) electrons to protons

**Solution:** The ratio of neutrons to protons determines the stability of an isotope.

**Answer:** 2

28 Which particle has the *least *mass?

(1) alpha particle

(2) beta particle (3) neutron

(4) proton

**Solution:** Table O on the Reference Table lists nuclear particles and their symbols. The mass number is on the top left corner of each symbol. Alpha particle has a mass of 4. Beta particle has a mass of 0. Neutron has a mass of 1 and proton has a mass of 1.

**Answer:** 2

29 The energy released during a nuclear reaction is a result of (1) breaking chemical bonds (2) forming chemical bonds (3) mass being converted to energy

(4) energy being converted to mass

**Solution:** Nuclear reactions release a lot of energy through the conversion of mass into energy.

**Answer: **3

30 The use of uranium-238 to determine the age of a geological formation is a beneficial use of (1) nuclear fusion (2) nuclear fission (3) radioactive isomers

(4) radioactive isotopes

**Solution: **Uranium-238 is a radioactive isotope that van be used to determine the age of a geological formation.

**Answer:** 4

June 2017

46 What is the mass of an original 5.60-gram sample of iron-53 that remains unchanged after 25.53 minutes? (1) 0.35 g

(2) 0.70 g

(3) 1.40 g

(4) 2.80 g

**Solution:** Table N on the Reference Table shows radioisotopes and their half lives. A half life is an amount of time that it takes for a radioisotopes mass to become a half of the original amount. Iron-53 has a half live of 8.51 min. Let's find out how many half lives are in 25.53 minutes.

25.53 minutes/8.51 min = 3 half lives.

The original amount is 5.60 grams. After first half life, we will have 5.60/2 = 2.8grams. After second half life, there will be 2.8/2= 1.4 grams. After third half life, there will be 1.4g/2 = 0.70 grams left

**Answer:** 2

47 Given the equation representing a nuclear reaction:

The particle represented by *X *is

**Solution:** To find X, we must find the mass number and the atomic number. To find mass number we add masses(on top) on the reactant side and make it equal to the sum of masses on the product side.

We do 1+x = 6+4 x=9. Mass must be 9, eliminating choices 3 and 4. Next we do the same for atomic number (bottom numbers). 1+y = 3+2 y=4. The atomic number is 4.

Next, we are going to check which element has an atomic number of 4 on the Periodic Table. Be has a mass number of 4.

**Answer: **2

48 Fission and fusion reactions both release energy. However, only fusion reactions (1) require elements with large atomic numbers

(2) create radioactive products (3) use radioactive reactants (4) combine light nuclei

**Solution:** Fusion is a nuclear reaction with small nuclei coming together such as hydrogens coming together to form a nucleus with a greater mass.

**Answer:** 4

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