June 2015 Chemistry Regents #21-25
Highlight to reveal answers and explanations
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Questions | Answer | Links | Explanations |
21. In which 1.0-gram sample are the particles arranged in a crystal structure? (1) CaCl2(s) (3) CH3OH(l) (2) C2H6(g) (4) Cal2(aq) | 1 | link | crystal structure is a solid |
22 When a reversible reaction is at equilibrium, the concentration of products and the concentration of reactants must be (1) decreasing (2) increasing (3) constant (4) equal | 3 | link | Con Con REqual at Equilibrium Concentrations are constant and the rates are equal |
23 In chemical reactions, the difference between the potential energy of the products and the potential energy of the reactants is equal to the (1) activation energy (2) ionization energy (3) heat of reaction (4) heat of vaporization | 3 | link | heat of reactions= PE products - PE reactants |
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24 What occurs when a catalyst is added to a chemical reaction? (l) an alternate reaction pathway with a lower activation energy (2) an alternate reaction pathway with a higher activation energy (3) the same reaction pathway with a lower activation energy (4) the same reaction pathway with a higher activation energy | 1 | link | catalyst speed up a reaction by lowing the activation energy |
25 What is the name of the compound with the formula CH3CH2CH2NH2? (1) l-propanol (2) l-propanamine (3) propanal (4) propanamide | 2 | link | this is the exact example on Table R under amine |
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