Chapter 10 Test Answers – Flashcards
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| Radioactive nuclei |
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| nuclei that undergo spontaneous changes and emit energy in the form of radiation |
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| radioactive decay |
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| a process in which an unstable nucleus changes energy state and in the process emits radiation |
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| alpha particle |
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| the particle that makes up alpha rays. It is identical to the helium nucleus and is composed of two protons and two neutrons |
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| beta particle |
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| the particle that make up beta rays. It is identical to an electron but is produced in the nucleus when a neutron is changed into a proton and an electron. |
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| gamma rays |
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| a high-energy ray that is like an x-ray but with a higher energy |
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| radioisotope |
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| an isotope of an element that emits nuclear radiation |
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| daughter nuclei |
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| the new nuclei produced when unstable nuclei undergo radioactive decay |
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| positronn |
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| a positively charged electron |
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| electron capture |
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| a mode of decay for some stable nuclei in which an electron from outside the nucleus is drawn into the nucleus, where it combines with a proton to form a neutron. |
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| half-life |
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| the time required for one half-life the unstable nuclei in a sample to undergo radioactive decay |
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| radical or free radical |
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| an electron-deficient particle that is very reactive |
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| acute radiation syndrome |
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| the condition associated with and following short-term exposure to intense radiation |
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| inverse square law of radiation |
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| a mathmatical way of saying that the intensity of radiation is inversely proportional to the square of the distance from the source |
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| physical unit of radiation |
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| a radiation measurement unit indicating the activity of the source of the radiation, for example the number of nuclear decays per minute |
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| biological unit of radiation |
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| a radiation measurement unit indicating the damage causedby radiation living tissues |
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| curie |
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| a physical unit of radiation measurement corresponding to 3.7 x 10 to the 10th nuclear disintegrations per second |
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| becquerel |
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| a physical unit of radiation measurement corresponding to one nuclear disintergration per second |
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| roentgen |
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| a biological unit of radiation measuremnt |
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| who discovered radioactivity |
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| henri becquerel |
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| what year was radioactivity discovered |
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| 1896 |
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| how did henri becquerel discover radiation |
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| photographic plate and rock containing uranium |
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| what two people did most of the early work on radioactivity |
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| pierre and marie curie |
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| transmutation |
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| any change from one element into another |
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| atomic number corresponds to what |
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| the number of protons |
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| mass number |
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| number of protons plus number of neutrons |
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| nucleon |
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| either a proton or a neutron |
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| are isotopes always unstable |
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| no |
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| what isotopes of hydrogen are stable or unstable |
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| 1H and 2H are stable, 3H are unstable |
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| which isotopes of carbon are stable and which are unstable |
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| 12C, and 13C are stable and 11C and 14C are unstable |
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| what is the mass and charge of gamma rays |
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| no mass or charge |
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| beta particles |
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| electrons from nucleus (not outer shell) |
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| radioisotope |
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| radioactive isotope |
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| during an equation for nuclear reactions, the number of nucleons |
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| stayes the same |
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| the total number of nucleons in reactants in the same as the the total number of |
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| nucleaons in the products |
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| how many protons and neutrons are in an alpha particle |
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| two of each |
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| where do alpha particles come from |
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| the nucleus |
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| what is the charge on the alpha particles |
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| plus 2 |
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| during positron emission a proton is converted into |
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| a positron plus a neutron |
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| during electron capture, an electron is sucked up by the nucleus and a |
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| proton and a proton is converted into a neutron |
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| definition of half-life |
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| the time it takes for half of a radioactive sample to undergo decay |
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| can you predict what the half life of a nuclide will be |
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| no it must be determined experimentally |
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| how are free radicals formed |
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| radiation may knock electrons out of compounds, which form free radicals that are very reactive |
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| which is more dangerous: long term or short term exposure to free radicals |
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| long term |
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| acute radiation syndrome is caused by |
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| high doses of radiation in a short period of time (tissue rapidly destroyed) |
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| radiation intensity varies with |
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| distance squared |
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| the farther away one is |
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| the lower the intensity of radiation felt |
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| rsoentgen are used with |
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| x-rays or gamma rays (measures ionizing ability) |
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| rad |
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| radiation absorbed dose |
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| what does rentgen measure |
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| ionizing ability |
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| what do rads measure |
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| energy transfered to the material |
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| what do rems measure |
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| health effects |
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| three ways to measure radiation |
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| geiger counter, film, scintillation counting |
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| how do they measure radiation in the lab (the most accurate)? |
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| scintillation counting |
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| tracers |
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| incorporate radioactive nuclides into biological molecules so can follow metabolilc processes |
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| what do you want to be accurate when using radiation for therapeutic uses |
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| the absporption to be very specific |
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| what tracer do they use to follow photosynthesis |
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| 14 CO2 |
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| artificial transmutation |
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| creation of a new isotope by bombardment of a material with particles |
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| nuclear fission |
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| a larder atom is split a part into smaller atoms |
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| is a lot of energy given off during nuclear fission |
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| yes |
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| what is the only natural element that will undergo fission |
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| 235 uranium |
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| what happens to the nucleus during fission |
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| it breaks apart and smaller atoms are created |
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| nuclear fusion |
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| elements melted together |
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| where does fusion occur naturally |
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| the sun |
