June 2016 Chemistry Regents #16-20
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Questions | Answer | Links | Explanations |
16 The collision theory states that a reaction is most likely to occur when the reactant particles collide with the proper (1) formula masses (2) molecular masses (3) density and volume (4) energy and orientation | 4 | effective collisions have proper orientation and enough energy | |
17 At STP, which sample contains the same number of molecules as 3.0 liters of H2(g)? (1) 1.5 L of NH3(g) (3) 3.0 L of CH4(g) (2) 2.0 L of CO2(g) (4) 6.0 L of N2(g) | 3 | Avogadro's hypothesis, same volumes of gas under the same conditions have equal numbers of molecules | |
18 The addition of a catalyst to a chemical reaction provides an alternate pathway that (1) increases the potential energy of reactants (2) decreases the potential energy of reactants (3) increases the activation energy (4) decreases the activation | 4 | catalysts lowers the activation energy | |
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19 A sample of water is boiling as heat is added at a constant rate. Which statement describes the potential energy and the average kinetic energy of the water molecules in this sample? (1) The potential energy decreases and the average kinetic energy remains the same. (2) The potential energy decreases and the average kinetic energy increases. (3) The potential energy increases and the average kinetic energy remains the same. (4) The potential energy increases and the average kinetic energy increases. | 3 | phase change==>potential energy change, and kinetic energy will remain constant | |
20 Entropy is a measure of the (1) acidity of a sample (2) disorder of a system (3) concentration of a solution (4) chemical activity of an element | 2 | Definition of entropy | |
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