June 2013 Chemistry Regents #11-20
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Questions | Answer | Links | Explanations |
11 A sample of CO2(s) and a sample of CO2(g) differ in their (1) chemical compositions (2) empirical formulas (3) molecular structures (4) physical properties | 4 | link | one is a gas and the other is a solid, so physically they are different |
12 Which statement defines the temperature of a sample of matter? (1) Temperature is a measure of the total electromagnetic energy of the particles. (2) Temperature is a measure of the total thermal energy of the particles. (3) Temperature is a measure of the average potential energy of the particles. (4) Temperature is a measure of the average kinetic energy of the particles. | 4 | link | definition of temperature. On every Regents, possibly more than once |
13 For a chemical reaction, the difference between the potential energy of the products and the potential energy of the reactants is equal to the (1) heat of fusion (2) heat of reaction (3) activation energy of the forward reaction (4) activation energy of the reverse reaction | 2 | link | definition of Heat of Reaction |
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14 Which equation represents sublimation? (1) Hg(l) ---> Hg(s) (3) NH3(g)--->NH3(l) (2) H2O(s)--->H2O(g) (4) CH4(l) --->CH4(g) | 2 | link | solid to a gas is sublimation |
15 Which statement describes the particles of an ideal gas, based on the kinetic molecular theory? (1) The motion of the gas particles is orderly and circular. (2) The gas particles have no attractive forces between them. (3) The gas particles are larger than the distances separating them. (4) As the gas particles collide, the total energy of the system decreases. | 2 | link | ideal gases don't attract |
16 Two grams of potassium chloride are completely dissolved in a sample of water in a beaker. This solution is classified as (1) an element (2) a compound (3) a homogeneous mixture (4) a heterogeneous mixture
| 3 | link | solution is a homogeneous mixture. It looks the same (pure) throughout. |
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17 Which compound has the strongest hydrogen bonding between its molecules? (1) HBr (3) HF (2) HCl (4) HI | 3 | link | H-bonding...look for the FON sisters HF, H2O, NH3 |
18 Powdered sulfur is yellow, and powdered iron is gray. When powdered sulfur and powdered iron are mixed at 20°C, the powdered iron (1) becomes yellow (3) remains ionic (2) becomes a liquid (4) remains magnetic | 4 | mixing is not reacting, the properties remain the same | |
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19 An effective collision between reactant particles requires the particles to have the proper (1) charge and mass (2) charge and orientation (3) energy and mass (4) energy and orientation | 4 | link | effective collisions require enough energy and the correct orientation to react |
20 Which term is defined as a measure of the disorder of a system? (1) heat (3) kinetic energy (2) entropy (4) activation energy | 2 | link | definition of entropy |