Monday, February 25, 2019
Ap Chemistry Free Response Answers
1. (a) I, III, and IV ar correct. II is not correct. To explain III, de Broglies equation states l = h/(mv), so nl = nh/(mv) = 2pi(r). Where l = wavelength, v = velocity of electron, n = some positive integer, r = distance of electron from center, m = aggregative of electron. Solve, certainize mvr = L = nh/2pi. (b) The current wave mechanical model for the blood corpuscle states that in that location argon an integer number of wavelengths in e actually standing(a)integer number (n). 2. (a) The eldest home base electrons in Lithium are the closest electrons to the nucleus. In addition, there are proportion anyy to a greater extent(prenominal) protons to electrons.This pulls the electrons change surface closer to the nucleus. And in Potassium, the satellite shell electrons are a hard distance from the nucleus. There are a greater number of protons than electrons however, the self-aggrandizing number of electrons dissipates the act. This is in addition to Lithium existe nce a some(prenominal) smaller neutral atom than Potassium because of the difference in the outer shells. (b) The outer shell for Cl is the same as Cl- however, Cl-has more than electrons beingattracted by the same number of protons. This weakens the standoff per electron. Since the attraction is weaker, the electrons are farther from the nucleus.Since the attraction is stronger for Cl, the electrons are closer to the nucleus. (c) Although the normal trend is for the ionisation heartiness to increase going to the right in a period, aluminum has a move ionization efficiency and magnesium has a raised ionization energy due to the electron configurations of these two ionizations. This reverses the invest of ionization energies. (d) The ionization energy increases each time an electron is removed because there are fewer electrons attracted by the same number of protons while magnesium starts offercelled at a relativelyhigh value because it begins in unmatchable of the pre ferred forms.The sec ionization energy is lowered because losing an electron forms a preferred form and because of this, this is a smaller than normal increase in ionization energy between the first and second ionization energies. The deuce-ace ionization energy is increased the most because it starts in the most ideal form. When you combine this with a lower than normal second ionization energy, you get a very large increase in ionization energy. 3. (a) As you go to the right of the period, there are more protons in the nucleus.The greater attraction makes it more difficult to remove electrons and first ionization energy is the energy necessary to remove an electron from a neutral atom. (b) Although the widely distributed trend is to have Boron with a higher first ionization energy than Berylium, Borons ionization potential is lowered and Beryliums ionization potential is raised, the order is reversed. (c) O loses one electron and makes it easier to remove the electron and lowe rs the ionization potential. For nitrogen, it more difficult to remove the electron and raises the ionization potential.And since Oxygens ionization potential is lowered and Nitrogens ionization potential is raised, the order is reversed. (d) Na has a lower first ionization energy than Li and also a lower ionization energy than Ne. Ne has the second highest first ionization energy of all the elements. 1s2is the most preferred electron configuration. s2p6of other shells are also highly preferred. Ne has the second highest first ionization potential because its 2s22p6. 4. (a) The lineament of decay anticipate for Carbon-11 would be positron emission. 116C - 115B + 01e (b) The type of decay expected for Carbon-14 would be Beta Decay as well. 46C - 147N + 0-1? (c) Gamma rays have no mass or charge, so they need not be shown in nuclear equations. (d) Measure the amount of Carbon-14 in the dead wood and study with the amount of Carbon-14 in a similar living object. 5. (a) 23494Pu - 230 92U + 42? (b) The lacking(p) mass has been converted into energy (E=mc2). (c) A line should be wasted curving down pat(p)ward from the alley of the dotted line. This willing represent the line of the alpha particles which are repelled by the positive plate and attracted by the nix one. A second line should be gaunt upward from the path of the dotted line.This will represent the path of the beta particles which are repelled by the negative plate and attracted by the positive one. The line should curve more than the one for the alpha particles. A third line should be drawn as a continuation of the dotted line. This will represent the da Gamma rays. (d) Incineration is a chemical serve up. The only thing any chemical process rout out do is connect radioactive atoms to other atoms, which has no effect on the radioactivity. 6. (a) As you go down the column in the bag metals, the outer shell electrons are farther from the nucleus.The attraction for the outer shell electrons is decreased and because the attraction is decreased, therefore the melting period decreases. (b) Intermolecular forces stop boiling and melting points. Halogens are all diatomic, which means they bond with themselves. In these diatomic compounds, the only intermolecular force isLondon forces. The larger molecules can form temporary dipoles easier than small molecules. The larger molecules as you go down the column have a greater attractive force. This increases the melting point as you go down the column. 7. a) As radius increases the heat of answer decreases. Which means less energy released by ionic attraction. (b) As ionization energy increases the heat of reaction decreases, which means more energy is required to form M2+ while other factors remain unchanged 8. Metals are peachy conductors of heat, generally malleable, and react by losing electrons to form cations. They tend to have s1, s2, s2p1, or s2p2as their outer shell. Most metals have just s1ors2. Nonmetals are poor con ductors of heat, brittle, and gain electrons when reacting with metals to form anions.Nonmetals have either 3, 4, 5, or 6 electrons in the p subshell in addition to s2of the same shell number. When the outlive subshell is a d, the outer shell is s2of the next shell. Occasionally there will be only 1 electron in the s subshell and this explains when the variation elements are metals. When the last subshell is a f, the outer shell is s2of the second higher shell and this explains when the lanthanides and actinides are metals. This proves how more than half of the periodic mesa are metals. 9. (a) you have not learned this one yet (b) F2has the highest negativismandelectron affinity.Thus it has the greatest attraction for extra electrons. F2 + 2e -2F 1 This makes the reaction more likely to occur. I2has the lowest electronegativity and electron affinity. Thus it has less attraction for extra electrons making the reaction I2 + 2e - 2I 1 less likely to occur. Because it can disperse the charge better, the reaction does occur. (c) The trend for alkali metals shows a very small variation in reducing strength without a real trend. Cesium has the lowest ionization potential and Lithium has the highest ionization potential. However, there is not a great difference in the alkali metals.
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