January 2008 Chemistry Regents #41-50

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

 

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Questions

Answer Explanations
41 A rigid cylinder with a movable piston contains a 2.0-liter sample of neon gas at STP. What is the volume of this sample when its temperature is increased to 30.C while its pressure is decreased to 90. kilopascals?
(1) 2.5 L    (3) 1.6 L
(2) 2.0 L    (4) 0.22 L
1 PV/T=PV/T

90(2)/303 =101.3(V)/273

P decreases and temp increases

volume should increase

42 Which compound is a saturated hydrocarbon?
(1) CH2CH2 (3) CH3CHO
(2) CH3CH3 (4) CH3CH2OH
2 hydrocarbon C and H only

saturated, alkanes, all single bonds CnH2n+2

43 A molecule of a compound contains a total of 10 hydrogen atoms and has the general formula CnH2n+2. Which prefix is used in the name of this compound?
(1) but-     (3) oct-
(2) dec-    (4) pent-
1 4 carbons

Table P

44 Reduction occurs at the cathode in
(1) electrolytic cells, only
(2) voltaic cells, only
(3) both electrolytic cells and voltaic cells
(4) neither electrolytic cells nor voltaic cells
3 both, never changes

 

Red Cat An OX

45 What are the products of a reaction between KOH(aq) and HCl(aq)?
(1) H2 and KClO    (3) KH and HClO
(2) H2O and KCl    (4) KOH and HCl
2 neutralization water and salt
46 Which volume of 0.10 M NaOH(aq) exactly neutralizes 15.0 milliliters of 0.20 M HNO3(aq)?
(1) 1.5 mL     (3) 3.0 mL
(2) 7.5 mL     (4) 30. mL
4 MV=MV

0.20(15.0)=0.10(V)

47 Which indicator, when added to a solution, changes color from yellow to blue as the pH of the solution is changed from 5.5 to 8.0?
(1) bromcresol green (3) litmus
(2) bromthymol blue (4) methyl orange
2 Table
4 each pH unit is 10 times the previous

acids (H+) low pH is more acidic

increases by 10

4 36.0s/7.2= 5 half lives

1/2   1/4  1/8  1/16  1/32

50 Which radioactive isotope is used in treating cancer?
(1) carbon-14      (3) lead-206
(2) cobalt-60       (4) uranium-238
2 just has to be memorized

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

 
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