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June 2011 Chemistry Regents #11-20
Highlight to reveal answers and explanations
Questions | Answer | Link | Explanations |
| 11 Which atom has the weakest attraction for the electrons in a bond with an H atom? (1) Cl atoms (2) F atom (3) O atom (4) S atom | 4 | Link | weakest attraction for an electron (lowest electronegativity-use Table S) |
| 12 Which substance cannot be broken down by a chemical change? (1) ammonia (2) mercury (3) propane (4) water | 2 | Link | definition of an element |
| 13 At standard pressure, how do the boiling point and freezing point of NaCl(aq) compare to the boiling point and freezing point of H2O(l)? (1) both the boiling point and the freezing point of NaCl(aq) are lower (2) both the boiling point and the freezing point of H2O(l)are lower (3) the boiling point of NaCl(aq) is lower and the freezing point of NaCl(aq) is higher (4)the boiling point of NaCl(aq) is higher and the freezing point of NaCl(aq) is lower | 4 | Link | boiling point increases and freezing point will decrease when a solute is added to a pure liquid |
| 14 The temperature of a sample of matter is a measure of the (1) average kinetic energy of its particles (2) average potential energy of its particles (3) total kinetic energy of it particles (4) total potential energy of its particles | 1 | Link | temperature is average kinetic energy |
| 15 According to the kinetic molecular theory, the particles of an ideal gas (1) have no potential energy (2) have strong intermolecular forces (3) are arranged in a regular, repeated geometric pattern (4) are separated by great distances, compared to their size | 4 | Link | Kinetic molecular theory is the theory of ideal gases gases are separated by large distances (or they may become liquids) |
| 16 Given the equation representing a closed system: N2O4(g) <=> 2NO2(g) Which statement describes this system at equilibrium? (1) The volume of the NO2(g) is greater than the volume of the N2O4(g) (2) The volume of the NO2(g) is less than the volume of the N2O4(g) (3) The rate of the forward reaction and the rate of the reverse reaction are equal (4) The rate of the forward reaction and the rate of the reverse reaction are unequal | 3 | Link | equilibrium =con con Requal concentrations are constant or the rates are equal to each other |
| 17 In a chemical reaction, the difference between the potential energy of the products and the potential energy of the reactants is equal to the (1) activation energy (2) kinetic energy (3) heat of reaction (4) rate of reaction | 3 | Link | definition of heat of reaction |
| 18 For a given chemical reaction, the addition of a catalyst provides a different pathway that (1) decreases the reaction rate and has a higher activation energy (2) decreases the reaction rate and has a lower activation energy (3) increases the reaction rate and has a higher activation energy (4) increases the reaction rate and has a lower activation energy | 4 | Link | definition of a catalyst, increase rate, by lower Act. Energy |
| 19 Which atom can bond with each other to form chains, rings or networks? (1) carbon atoms (2) hydrogen atoms (3) oxygen atoms (4) nitrogen atoms | 1 | Link | first question of the organic chemistry section carbon |
| 20 A molecule of an unsaturated hydrocarbon must have (1) at least on single carbon-carbon bond (2) at least one multiple carbon-carbon bond (3) two or more single carbon-carbon bonds (4) two or more multiple carbon-carbon bonds | 2 | Link | definition of Unsaturated hydrocarbon= "not all single bonds" |