January 2005 Chemistry Regents #41-50

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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
	3	A Solid, Silver
	3	there are 9 neutrons and 7 protons the ratio is not 1:1
43 Which of these changes produces the greatest increase in entropy? (1) CaCO3(s) �--> CaO(s) + CO2(g) (2) 2 Mg(s) + O2(g) �--> 2 MgO(s) (3) H2O(g) �--> H2O(l) (4) CO2(g) �--> CO2(s)	1	Solid--> Solid and a GAS
	4	2 functional groups present amine and acid
45 Which half-reaction can occur at the anode in a voltaic cell? (1) Ni2+ + 2e�--->  Ni     (3) Zn�--> Zn2+ + 2e- (2) Sn + 2e-�--> Sn2+    (4) Fe3+�--> Fe2+ + e-	3	oxidation, charge goes up, electrons on the more positive side
46 Given the reaction: Ba(OH)2(aq) + H2SO4(aq) -->BaSO4(s) + 2 H2O(l) + energy As the barium hydroxide solution is added to the solution of sulfuric acid, the electrical conductivity of the acid solution decreases because the (1) volume of the reaction mixture increases (2) temperature of the reaction mixture decreases (3) concentration of ions increases (4) concentration of ions decreases	4	H+ and OH- are creating H2O so there are less ions present
47 Which chemical equation represents the reaction of an Arrhenius acid and an Arrhenius base? (1) HC2H3O2(aq) + NaOH(aq) �--> NaC2H3O2(aq) + H2O(l) (2) C3H8(g) + 5 O2(g)�-->  3 CO2(g) + 4 H2O(l) (3) Zn(s) + 2 HCl(aq)�--> ZnCl2(aq) + H2(g) (4) BaCl2(aq) + Na2SO4(aq) ��--> BaSO4(s) + 2 NaCl(aq)	1	neutralization
48 Based on Reference Table F, which of these saturated solutions has the lowest concentration ofdissolved ions? (1) NaCl(aq)       (3) NiCl2(aq) (2) MgCl2(aq)     (4) AgCl(aq)	4	the insoluble one
	2	56.2y/28.3y=2 half lives 1--> 1/2--> 1/4
	4	o1B