Chapter 19 Study Book
Everyone receives background radiation. This comes from various sources: the ground, medical procedures, radon in the air, etc. On average, people in the United States receive about
1 mrem of radiation a day.
It will take _____ half-lives for 75% of the original amount of a radioactive isotope to decay.
2
When the isotope uranium- absorbs a neutron, it ultimately produces another fissionable element known as plutonium.
238
The isotope 23V51 has neutrons in its nucleus
28
Match the numbers (in the left column) with the names these numbers represent (in the right column) for the isotope 7N15
7--->Atomic number N---->Chemical symbol 15---->Mass number
If the nucleus of atom Y is 18 times heavier than that of hydrogen and element Y has an atomic number of 8, then the number of protons is and the number of neutrons is
8 10
When an element 88X226 emits an alpha particle, the resultant element will be
86Y222
How can a fission reaction be initiated?
A fission reaction can be initiated by high-energy neutrons. A fission reaction can be initiated by high-energy alpha particles. A fission reaction can be initiated by low-energy neutrons. A fission reaction can be initiated by high-energy protons.
Select the characteristics of a proton.
A proton is much more massive than an electron. A proton has a positive charge which is the same in magnitude as an electron's.
Why is energy released in a nuclear reaction?
Because of Einstein's famous equation E = mc2. Because the mass of the parent nucleus and the bombarding particle is more than the combined mass of the reaction products
neutrons are more likely to be absorbed by uranium-235 and initiate a fission reaction, while neutrons are more likely to be absorbed by uranium-238.
Blank 1: Slow Blank 2: fast, energetic, speedy, or quick
Water is used both as a and a in nuclear reactors.
Blank 1: moderator Blank 2: coolant
When nitrogen nuclei are bombarded by alpha particles, are emitted. This reaction is called a reaction
Blank 1: protons Blank 2: nuclear or fusion
What are the similarities between a plutonium bomb and a uranium bomb? (Check all that apply.)
Both plutonium and uranium bombs require chain reactions. Both plutonium and uranium bombs produce enormous amount of energy. Both plutonium and uranium bombs reaction starts with a subcritical mass of fuel. Both plutonium and uranium bombs employ nuclear fission.
How does a fission reactor produces energy to drive electric turbines?
By making use of Einstein's famous equation E = mc2. By splitting heavy nuclei into smaller ones thus releasing energy.
Which of the following equations best explain the energy released in a fusion reaction?
E = mc2
In a fusion reaction, deuterium (H2) and tritium (H3) nuclei fuse to form an alpha particle plus a neutron. Consequently, an amount of energy will be released according to
E= m c2. mass to energy conversion.
Match the statements on the left with the suitable entries on the right.
Fast neutrons are more likely to be absorbed by---->plutonium-239. Slow neutrons are more likely to be absorbed by--->uranium-235.
Match the particles and rays on the left column with their characteristic on the right column.
Gamma radiation----->has no charge or mass. Beta particle---->has the mass of a single electron. Alpha particle----->has two protons and two neutrons.
How does the number of neutrons most typically compare to the number of protons in a nucleus?
Greater than Equal to
Match the equations on the left with the equation entries on the right.
He24He24------>Li36 +H12⇒He24 +? Li36 +H12⇒He24 +? O817O817----->He35 +N714⇒? + H11 He35 +N714⇒? + H11 3 01n3 01n---->U92235 + n01⇒Ba65144 + Kr3889 + ?
Which of the following statements are true for a fission chain reaction? (Check all that apply.)
In a fission chain reaction, a rapid growth of subsequent fission reactions takes place. In a fission chain reaction, enormous energy is produced. In a fission chain reaction, extra neutrons are produced in each step.
What happens during a nuclear fusion reaction? (Check all that apply.)
In nuclear fusion, energy is produced. In nuclear fusion, smaller nuclei fuse to form a larger nucleus.
If the half-life of a radioactive isotope X is about 10 days, which of the following statements are correct? (Check all that apply.)
It takes 10 days for half of the amount of X to decay. In 20 days, there will be one-fourth of the original amount of X left.
What are the policies proposed by the government on fission reactors' waste disposal? (Check all that apply.)
Leaving the remaining uranium in the waste without separating it. Burying the waste in solid rock formations.
Rank the following nuclei based on the number of neutrons with the highest one at the top.
Nucleus X is 12 times heavier than the hydrogen nucleus and has an atomic number of 5 Nucleus Y is 12 times heavier than the hydrogen nucleus and has an atomic number of 6 Nucleus Z is 13 times heavier than the hydrogen nucleus and has an atomic number of 8
Rank the following nuclei based on the excess neutrons they are likely to produce when they split.
Nucleus Y with proton to neutron ratio of 0.6 Nucleus Y with proton to neutron ratio of 0.6 Nucleus Y with proton to neutron ratio of 0.6
Which of the following statements are true about plutonium? (Check all that apply.)
Plutonium is fissionable by neutrons. Plutonium is a by-product of a fission reactor. Plutonium is a decay product of uranium.
Match the atomic components (in the left column) with the appropriate numbers of these components (in the right column) for the isotope 29Cu65.
Proton---->29 Neutron---->36 Neuclons---->65
What are the reasons for slowing neutrons down to achieve chain reactions? (Check all that apply.)
Slow neutrons are more likely to be absorbed by uranium-235. Slow neutrons are less likely to be absorbed by uranium-238.
Which of the following statements are true about the atomic number of an element?
The atomic number of an element determines its chemical properties. The atomic number of an element is the number of electrons needed outside the nucleus to make the atom neutral. The atomic number of an element is the number of protons in the nucleus of the atom.
Why did the discovery of neutrons lead to the discovery of nuclear fission? (Check all that apply.)
The discovery of neutrons lead to the discovery of nuclear fission because, the neutrons are not repelled by the nucleus. The discovery of neutrons lead to the discovery of nuclear fission because, the neutrons are neutral.
Why is radioactivity hazardous to health?
The emitted radiation can alter chemical compounds in our body.
Which of the following statement is true for gamma rays?
The gamma rays are high-energy radiation with no mass or charge.
Which of the following use nuclear fusion reaction as the energy source? (Check all that apply.)
The sun Thermonuclear bombs
True or false: The decay process can be represented by an exponential decay curve, because mathematically it can be represented by an exponential function.
True
What are the differences between Plutonium bombs and Uranium bombs? (Check all that apply.)
Unlike uranium-235, plutonium-239 absorbs fast neutrons. Plutonium bombs rely on implosions to produce a critical mass.
What is uranium enrichment? (Check all that apply.)
Uranium enrichment means decreasing the content of uranium-238 in natural uranium samples. Uranium enrichment means increasing the content of uranium-235 in natural uranium samples.
Which of the following is true about uranium isotopes? (Check all that apply.)
Uranium-235 is likely to split when bombarded by slow neutrons. Uranium-238 is more abundant in nature.
Why a chain reaction does not occur for uranium ore? (Check all that apply.)
Uranium-235 is more likely to absorb the extra neutrons. Because of the low content of the fissionable uranium-235.
Match the statements on the right side with the suitable entry on the left.
Uranium-235---->is a naturally scarce, fissionable uranium isotope. Its nuclei split when bombarded by neutrons, releasing enormous energy and extra neutrons. Uranium-238----->is the most naturally abundant uranium isotope. It absorbs neutrons and is less likely to undergo fission reaction.
Isotopes are detected by passing nuclei of known velocity through a magnetic field and observing how much their paths are bent under the influence of
a magnetic force
Gamma decay results in
a more stable version of the same element.
The role of control rods in the nuclear reactor is to neutrons to control the rate of the reaction.
absorb
The conservation of linear momentum in alpha decay requires that
after the decay, the alpha particle and the daughter nucleus emerge in opposite direction. after the decay, the alpha particle is always faster than the daughter nucleus.
An element 88X226 is radioactive and decays into 86Y222. The radioactive process that has occurred is called decay.
alpha
If a particle and its anti-particle interact, they will each other and release energy.
annihilate, destroy, or cancel
In a nuclear reaction
at least one nucleus will transform to another. the charge and mass numbers add up to the same total before and after the reaction.
The number determines how many electrons are outside of a neutral atom, which in turn determines the chemical properties of the atom
atomic
The rapid growth of the number of subsequent fission reactions due to excess neutrons produced in each fission is called a reaction.
chain
Beta decay could lead to the emission of
electrons and positrons
When the change in a number (such as decays or additional events) depends proportionally on that number, this condition leads to decay or growth.
exponential
Nuclear is the process whereby one massive nucleus splits into smaller nuclei.
fission
A nuclear reaction that combines small nuclei to form larger ones is called a reaction. (Use one word in the blank.)
fusion
Recent technologies being used to establish economically feasible fusion reactors include
laser. magnetism.
The advantage of using heavy water instead to light (ordinary) water in nuclear reactors is that heavy water is likely to absorb neutrons.
less
The role of a in the nuclear reactor is to slow down neutrons so that they are more likely to be absorbed by uranium-235.
moderator
In general, but with a few exceptions, the number is greater than the atomic number.
neutron
The charge of a proton is equal in magnitude to an electron's but is
positive
The nucleus of the hydrogen atom consists of a single
proton
In fission reactors, most of the nuclear waste is
radioactive
In a fission reaction, subcritical state means that
the chain reaction cannot be sustained. the mass of the initial fissionable fuel is less than the critical mass.
Producing commercial power from fusion has not been achieved mainly because of
the enormous temperature required for its operation.
In a fission reaction, supercritical state means that
the mass of the initial fissionable fuel is more than the critical mass.
Nuclear fission releases extra neutrons because
the parent nucleus contains significantly more neutrons than protons. smaller nuclei have a lower neutron to proton ratio compared with bigger nuclei.
The main source of nuclear waste in a fission reactor come from
the spent fuel rods.
When a neutron is absorbed by the uranium-235 nucleus
the uranium nucleus splits into smaller nuclei and more neutrons are emitted. a nuclear reaction occurs.
Isotopes of the same element have different masses because
they have a different number of neutrons.
The main characteristic of radioactive nuclei is that they are
unstable
In fusion reactors, the chain reaction requires
very high temperatures.
