August 2009 Chemistry Regents #31-40

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

Questions 51-55 Questions56-58 Questions 59-63 Question 64 Questions 65-67 Questions 68-72 Questions 73-76 Questions 77-79 Questions 80-81

 

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Questions

Answer Explanations
31 Which electron configuration represents an
excited state for a potassium atom?
(1) 2-8-7-1    (3) 2-8-8-1
(2) 2-8-7-2    (4) 2-8-8-2
2 19 electrons and 1 is promoted
32 A sample of an element is malleable and can conduct electricity. This element could be
(1) H      (3) S
(2) He    (4) Sn
4 properties of  metals
33 Which general trend is demonstrated by the Group 17 elements as they are considered in order from top to bottom on the Periodic Table?
(1) a decrease in atomic radius
(2) a decrease in electronegativity
(3) an increase in first ionization energy
(4) an increase in nonmetallic behavior
2 Table S
34 Which element is a liquid at 758 K and standard pressure?
(1) gold      (3) platinum
(2) silver     (4) thallium
4 Table S Melting Points
35 Which equation represents a decomposition reaction?
(1) CaCO3(s) ==>CaO(s) + CO2(g)
(2) Cu(s) + 2AgNO3(aq)  ==>2Ag(s) + Cu(NO3)2(aq)
(3) 2H2(g) + O2(g)  ==>2H2O(l)
(4) KOH(aq) + HCl(aq)  ==>KCl(aq) + H2O(l)
1 decomp  AB==> A + B
36 A compound has the empirical formula CH2O and a gram-formula mass of 60. grams per mole. What is the molecular formula of this compound?
(1) CH2O         (3) C3H8O
(2) C2H4O2        (4) C4H8O4
2 CH2O= 30g/mol

 C2H4O2 =60g/mol

37 Which formula represents strontium phosphate?
(1) SrPO4       (3) Sr2(PO4)3
(2) Sr3PO8     (4) Sr3(PO4)2
4 Sr2+   PO43-

Sr3(PO4)2

4 Ionic

Metals no dots + charge

Nonmetals 8 dots  - charge

39 Which statement describes the transfer of heat energy that occurs when an ice cube is added to an insulated container with 100 milliliters of
water at 25C?
(1) Both the ice cube and the water lose heat energy.
(2) Both the ice cube and the water gain heat energy.
(3) The ice cube gains heat energy and the water loses heat energy.
(4) The ice cube loses heat energy and the water gains heat energy.
3 heat  goes from HOT TO COLD
40 What is the mass of NH4Cl that must dissolve in 200. grams of water at 50.C to make a saturated solution?
(1) 26 g     (3) 84 g
(2) 42 g     (4) 104 g
4 Table G...DOUBLE the results it is 200g of Water

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

Questions 51-55 Questions56-58 Questions 59-63 Question 64 Questions 65-67 Questions 68-72 Questions 73-76 Questions 77-79 Questions 80-81

 
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