New York State Chemistry Regents June 2008
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Chemistry Regents June 2008 - Question 28 |
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Written by The Chemistry Wizard
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(3) Transmutation is the correct answer.
This questions tests your knowledge of nuclear reactions. Unlike normal chemical reactions that form molecules, nuclear reactions result in the transmutation of one element into a different isotope or a different element altogether (remember that the number of protons in an atom defines the element, so a change in protons results in a change in the atom).
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Last Updated on Friday, 13 March 2009 11:11 |
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Chemistry Regents June 2008 - Question 29 |
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Written by The Chemistry Wizard
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(2) A beta particle is the correct answer.
When an atom emits a β particle, the atom's mass will not change (since there is no change in the total number of nuclear particles), however the atomic number will increase by one (because the neutron transmutated into an additional proton).
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Chemistry Regents June 2008 - Question 30 |
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Written by The Chemistry Wizard
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(4) It is difficult to dispose of nuclear wastes.
It is difficult to dispose of nuclear wastes because once it is created it exists forever (or close to forever depending on the amount of radioactive material involved). There is a process called the "half life', some isotopes degrade rapidly, others last for thousands of years. All you can do is isolate it from anything that it might damage.
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Chemistry Regents June 2008 - Question 31 |
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Written by The Chemistry Wizard
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(4) spectra of elements with multielectron atoms is the correct answer.
Multielectron atoms are atoms with more than one electron in the outer shell. The wave mechanical model, influenced by the Heisenberg uncertainty principle, says that electrons do not orbit in fixed orbits. In fact, it's impossible to know both the position and momentum of a particle like an electron. Instead the wave mechanical model uses the Schroedinger equation to predict the probabilities of where the electron may be positioned at any given time (without saying with any certainty where the electron actually is).
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Chemistry Regents June 2008 - Question 50 |
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Written by The Chemistry Wizard
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(1) is the correct answer. (1.3x109 y).
25 g – initial time
12.5 g – 1st half life
6.25 g – 2nd half life
3.125 g - after 3.9 x 109 y (3rd half life)
By simple division, we can see that the time 3.9 x 109 y represents 3 half lives. By dividing this number by 3, we can see that the half life of K-40 is (1.3x109 y).
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Chemistry Regents June 2008 - Question 72 |
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Written by The Chemistry Wizard
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Chemistry teachers, please submit an answer to this question to help us complete this project!
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Last Updated on Friday, 13 March 2009 18:00 |
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Chemistry Regents June 2008 - Question 73 |
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Written by The Chemistry Wizard
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The Balmer series are wavelengths of light that are produced by atoms, when an electron falls from a higher to a lower energy state, light is emitted.
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Chemistry Regents June 2008 - Question 77 |
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Written by The Chemistry Wizard
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This is alpha decay, which means that americium emits an alpha particle, which is the same as a helium-4 nucleus, and both mass number and
atomic number are the same.
Am24195 produces He42 + Np23793
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Chemistry Regents June 2008 - Question78 |
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Written by The Chemistry Wizard
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Fr-220 has a shorter half-life so decays more quickly.
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Chemistry Regents June 2008 - Question 79 |
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Written by The Chemistry Wizard
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The flow of ions into the detector maintains a steady electric current. When the smoke particles mix with the ions, they interrupt the flow and cause the alarm to sound.
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