January 2006 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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41 A student adds solid KCl to water in a flask. The flask is sealed with a stopper and thoroughly shaken until no more solid KCl dissolves. Some
solid KCl is still visible in the flask. The solution in the flask is
(1) saturated and is at equilibrium with the solid KCl
(2) saturated and is not at equilibrium with the solid KCl
(3) unsaturated and is at equilibrium with the solid KCl
(4) unsaturated and is not at equilibrium with the solid KCl		1saturated if full. Saturated is at equilibrium.
42 Given the incomplete equation for the combustion of ethane:
2C2H6 + 7O2==>4CO2 + 6 ____
What is the formula of the missing product?
(1) CH3OH    (3) H2O
(2) HCOOH (4) H2O2		3combustion CO2 and H2O are the products
2exothermic, energy is released

Act. Energy 50kJ -40kJ=10kJ

1See table R
45 Which formula represents an unsaturated  hydrocarbon?
(1) CH2CHCl         (3) CH3CH2CH3
(2) CH3CH2Cl       (4) CH3CHCH2		4hydrocarbon-hydrogen and carbon only

unsaturated double or triple bonded

3-alkane C3H8  4-alkene C3H6

46 Given the balanced equation for an organicreaction:
C2H2 + 2Cl2 ==> C2H2Cl4
This reaction is best classified as
(1) addition          (3) fermentation
(2) esterification   (4) substitution		1unsaturated==> addition
47 Which indicator is yellow in a solution with a pH of 9.8?
(1) methyl orange       (3) bromcresol green
(2) bromthymol blue   (4) thymol blue		1Tabl;e M
48 How many milliliters of 0.100 M NaOH(aq) would be needed to completely neutralize 50.0 milliliters of 0.300 M HCl(aq)?
(1) 16.7 mL (3) 150. mL
(2) 50.0 mL (4) 300. mL		3Table T

 MV=MV

2find the missing mass and atomic number

look up atomic number to find element on PT

50 The decay of which radioisotope can be used to estimate the age of the fossilized remains of an insect?
(1) Rn-222      (3) Co-60
(2) I-131         (4) C-14		4organic dating use C-14

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