August 2006 Chemistry Regents #11-20

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Questions 1-10 Questions 11-20 Questions 21-30 Questions 31-40 Questions 41-50

Other Regents Exams

Questions	Answer	Explanations
11 The degree of polarity of a chemical bond in a molecule of a compound can be predicted by determining the difference in the (1) melting points of the elements in the compound (2) densities of the elements in the compound (3) electronegativities of the bonded atoms in a molecule of the compound (4) atomic masses of the bonded atoms in a molecule of the compound	3	Bond=bend= Bonds (think) Electronegativity Differences
12 Which statement best describes the shape and volume of an aluminum cylinder at STP? (1) It has a definite shape and a definite volume. (2) It has a definite shape and no definite volume. (3) It has no definite shape and a definite volume. (4) It has no definite shape and no definite volume.	1	Al is a solid at STP
13 Which two substances can not be broken down by chemical change? (1) C and CuO     (3) CO2 and CuO (2) C and Cu        (4) CO2 and Cu	2	Definition of Elements
14 Which compound is insoluble in water? (1) BaSO4       (3) KClO3 (2) CaCrO4     (4) Na2S	1	Use table F
15 A sample of a gas is contained in a closed rigid cylinder. According to kinetic molecular theory, what occurs when the gas inside the cylinder is heated? (1) The number of gas molecules increases. (2) The number of collisions between gas molecules per unit time decreases. (3) The average velocity of the gas molecules increases. (4) The volume of the gas decreases.	3	Closed Container. Temperature is avg. KE= motion
16 Which statement best describes how a catalyst increases the rate of a reaction? (1) The catalyst provides an alternate reaction pathway with a higher activation energy. (2) The catalyst provides an alternate reaction pathway with a lower activation energy. (3) The catalyst provides the same reaction pathway with a higher activation energy. (4) The catalyst provides the same reaction pathway with a lower activation energy.	2	Definition of a catalyst (always on test)
17 The compounds 2-butanol and 2-butene both contain (1) double bonds, only    (3) carbon atoms (2) single bonds, only      (4) oxygen atoms	3	but-= 4 carbon atoms
	2	Avogadro's hypothesis, same conditions, same volume, same # molecules
19 A chemical reaction is at equilibrium. Compared to the rate of the forward reaction, the rate of the reverse reaction is (1) faster and more reactant is produced (2) faster and more product is produced (3) the same and the reaction has stopped (4) the same and the reaction continues in both directions	4	Con Con Requal (Equilibrium) Concentrations are constant because the rates are equal
20 Which organic compound is a saturated hydrocarbon? (1) ethyne     (3) ethanol (2) ethene     (4) ethane	4	Saturated all single bonds, ALKANE