January 2009 Chemistry Regents #41-50

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

Questions 51-53 Questions 54-55 Questions 56-58 Questions 59-61 Questions 62-64 Questions 65-66 Questions 67-68 Questions 69-71 Questions 72-74 Questions 75-77 Questions 78-79 Questions 80-81

 

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Questions

AnswerExplanations
4elements same color

compound multicolored

1melting point the lower plateau

from 2 to 5 minutes

so 3 minutes to melt

43 Which compound is an alkyne?
(1) C2H2 (3) C4H8
(2) C2H4 (4) C4H10		1Table Q use the general formula
44 What is the oxidation number of sulfur in Na2S2O3?
(1) -1      (3) +6
(2) +2     (4) +4		2+2 +2S-6=0
1unsaturated (has a double or triple bond)

hydrocarbon  made of hydrogen and carbon only

46 Which balanced equation represents a redox
reaction?
(1) PCl5 ==> PCl3 + Cl2
(2) KOH + HCl ==> KCl + H=O
(3) LiBr==> Li+ + Br=
(4) Ca2+ + SO42- ==>CaSO4		1redox look for the free element Cl2
47 A 25.0-milliliter sample of HNO3(aq) is neutralized by 32.1 milliliters of 0.150 M KOH(aq). What is the molarity of the HNO3(aq)?
(1) 0.117 M    (3) 0.193 M
(2) 0.150 M    (4) 0.300 M		3MV=MV

(25.0mL)M=32.1mL x 0.150M

48 Which nuclide has a half-life that is less than one minute?
(1) cesium-137      (3) phosphorus-32
(2) francium-220    (4) strontium-90		2Table N
3use the symbol to determine the number of protons (atomic #)

neutrons = mass number -protons

50 Cobalt-60 and iodine-131 are radioactive isotopes that are used in
(1) dating geologic formations
(2) industrial measurements
(3) medical procedures
(4) nuclear power		3just memorize it

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

Questions 51-53 Questions 54-55 Questions 56-58 Questions 59-61 Questions 62-64 Questions 65-66 Questions 67-68 Questions 69-71 Questions 72-74 Questions 75-77 Questions 78-79 Questions 80-81

 
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