June 2023 Chemistry Regents #16-20
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Questions |
Answer | Links |
Explanations |
| 16. The melting of an ice cube is an example of an 1. endothermic, chemical change 2. endothermic, physical change 3. exothermic, chemical change 4. exothermic, physical change |
2 | it takes energy to melt ice (endo), it is still water (physical) | |
| 17. Which statement explains the low
boiling point of hydrogen, H2, at standard pressure? 1. Hydrogen has strong covalent bonds. 2. Hydrogen has weak covalent bonds. 3. Hydrogen has strong intermolecular forces. 4. Hydrogen has weak intermolecular forces. |
4 | intermolecular forces determine boiling points | |
| 18. In chemical reactions, which term is defined as
the difference between the potential energy of the products and the
potential energy of the reactants? 1. heat of fusion 2. heat of reaction 3. thermal conductivity 4. electrical conductivity |
2 | definition of heat of reaction, the others don't make sense | |
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| 19. Which phrase describes what happens to the
reaction pathway and activation energy of a reaction to which a
catalyst is added? 1. the same pathway with the same activation energy 2. the same pathway with a lower activation energy 3. a different pathway with the same activation energy 4. a different pathway with a lower activation energy |
4 | catalyst lower the act. energy by taking a different route. Through the tunnel vs. over the mountain. | |
| 20. An atom of which element is bonded to the carbon
atom in the amide functional group? 1. iodine 2. nitrogen 3. phosphorous 4. sulfur |
2 | Start of Organic Chem. section. look up functional groups on Table R | |
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