June 2017 Chemistry Regents #11-15
Highlight to reveal answers and explanations
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Questions | Answer | Links | Explanations |
11. What is the number of electrons shared between the atoms in an I2 molecule? (1) 7 (3) 8 (2) 2 (4) 4 | 2 | link | I-I has a single bond a covalent bond contains 2 shared electrons |
12 Which substance has nonpolar covalent bonds? (1) Cl2 (3) SiO2 (2) SO3 (4) CCl4 | 1 | link | nonpolar bonds have zero difference in electron negativity this happens when you have the same element bonded to itself |
13 Compared to a potassium atom, a potassium ion has (1) a smaller radius (2) a larger radius (3) fewer protons (4) more protons | 1 | link | metals are LOSERs...they lose their valence shell of electrons and get small...generally |
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14 Which form of energy is associated with the random motion of particles in a gas? (l) chemical (2) electrical (3) nuclear (4) thermal | 4 | link | motion is kinetic energy....average kinetic energy is proportional to temperature...thermal |
15 The average kinetic energy of water molecules decreases when (1) H2O(l) at 337 K changes to H2O(l) at 300. K (2) H2O(l) at 373 K changes to H2O(g) at 373K (3) H2O(s) at 200. K changes to H2O(s) at 237 K (4) H2O(s) at 273 K changes to H2O(l) at 273 K | 1 | link | since average KE is "temperature" find the answer where temperature decreases phases are to be ignored |
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