January 2011 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 56-57 Questions 58-59 Questions 60-61 Questions 62-63 Questions 64-65 Questions 66-68 Questions 69-71 Questions 72-74 Questions 75-77 Questions 78-80 Questions 81-83

 

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Questions

Answer Explanations
41 The temperature of a sample of water changes from 10C to 20C when the sample absorbs 418 joules of heat. What is the mass of the sample?
(1) 1 g     (3) 100 g
(2) 10 g   (4) 1000
2 q=mCDT

m=q/CDT

10g=( 418J/(4.18J/gC) x10C)

42 Given the reaction at 101.3 kilopascals and 298 K:

hydrogen gas + iodine gas → hydrogen iodide gas

This reaction is classified as
(1) endothermic, because heat is absorbed
(2) endothermic, because heat is released
(3) exothermic, because heat is absorbed
(4) exothermic, because heat is released

1 Table I

delta H=+53kJ

endothermic absorbs

43 Given the equation:


Which type of reaction is represented by this equation?
(1) combustion     (3) polymerization
(2) esterification    (4) substitution

3 addition polymerization

formed long repeating chain

44 The graph below represents the uniform heating of a sample of a substance starting as a solid below its melting point

Which statement describes what happens to the energy of the particles of the sample during time interval DE?
(1) Average kinetic energy increases, and potential energy remains the same.
(2) Average kinetic energy decreases, and potential energy remains the same.
(3) Average kinetic energy remains the same, and potential energy increases.
(4) Average kinetic energy remains the same, and potential energy decreases.

3 DE is a plateau ,phase change,

potential energy changes (increase, heating curve)

kinetic remains the same (temperature is constant)

45 Which molecule has a nonpolar covalent bond? 1 nonpolar bond

two of the same elements bonded

46 Given the equation representing a reaction at equilibrium:
N2(g) + 3H2(g) <==>2NH3(g)
What occurs when the concentration of H2(g) is increased?
(1) The equilibrium shifts to the left, and the concentration of N2(g) decreases.
(2) The equilibrium shifts to the left, and the concentration of N2(g) increases.
(3) The equilibrium shifts to the right, and the concentration of N2(g) decreases.
(4) The equilibrium shifts to the right, and the concentration of N2(g) increases.
3 adding H2 shifts right

reactants decrease and products increase

47 Which ionic equation is balanced?
(1) Fe3++ Al → Fe2++ Al3+
(2) Fe3++ 3Al → Fe2++ 3Al3+
(3) 3Fe3++ Al → 3Fe2++ Al3+
(4) 3Fe3++ Al → Fe2++ 3Al3+
3 charges in must equal charges out

and atoms in equal atoms out

48 The table below gives information about four aqueous solutions at standard pressure.

Which list of solutions is arranged in order from highest boiling point to lowest boiling point?
(1) A, B, D, C    (3) C, D, B, A
(2) A, C, B, D    (4) D, B, C, A

1 highest boiling point depends on concentration of particles (ions)

ionic compounds break up in water

A 2 x 3=6M of ions

B. 2 x 2=4M

C. 1 x 1=1M

D. 1 x 3=3M

49 What is the total number of years that must pass before only 25.00 grams of an original 100.0-gram sample of C-14 remains unchanged?
(1) 2,865 y   (3) 11,460 y
(2) 5,730 y   (4) 17,190 y
3 100-->50-->25

2 half lives

2 x 5730y

table N

50 Which radioisotope is used for diagnosing thyroid disorders?
(1) U-238     (3) I-131
(2) Pb-206   (4) Co-60
3 thyroid =iodine

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

Questions 51-53 Questions 54-55 Questions 56-57 Questions 58-59 Questions 60-61 Questions 62-63 Questions 64-65 Questions 66-68 Questions 69-71 Questions 72-74 Questions 75-77 Questions 78-80 Questions 81-83

 
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