June 2015 Chemistry Regents #11-15
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Questions | Answer | Links | Explanations |
| 11. All atoms of uranium have the same (1) mass number (2) atomic number (3) number of neutrons plus protons (4) number of neutrons plus electrons | 2 | Link | Uranium atoms must have the same atomic number or it is not uranium |
| 12. The concentration of a solution can be expressed in (1) kelvins (2) milliliters (3) joules per kilogram (4) moles per liter | 4 | Link | Molarity =moles of solute/liter of solution |
| 13 Compared to the boiling point and the freezing point of water at 1 atmosphere, a 1.0 M CaCl2(aq) solution at 1 atmosphere has a (1) lower boiling point and a lower freezing point (2) lower boiling point and a higher freezing point (3) higher boiling point and a lower freezing point (4) higher boiling point and a higher freezing point | 3 | Link | solutions have higher boiling point and a lower freezing point than the pure solvent |
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| 14 According to the kinetic molecular theory, which statement describes an ideal gas? (1) The gas particles are diatomic (2) Energy is created when the gas particles collide (3) There are no attractive forces between the gas particles (4) The distance between the gas particles is small, compared to their size. | 3 | Link | ideal gases have no attraction or they might become liquids under certain conditions |
| 15 Which physical change is endothermic? (1) CO2(s)-->CO2(g) (3) CO2(g)-->CO2(l) (2) CO2(l)-->CO2(s) (4) CO2(g)-->CO2(s) | 1 | Link | S L G problem 1 S---->G 3 L<---G 2 S<----L 4 S<----G 3 are wrong and 1 is right |
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