June 2012 Chemistry Regents #41-50

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

Question 51 Questions 52-55 Questions 56-59 Questions 60-62 Questions 63-65 Questions 66-68 Questions 69-71 Questions 72-75  Questions 76-78  Questions 79-81  Questions 82-85

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41  At 50.oC and standard pressure, intermolecular forces of attraction are strongest in a sample of

(1)  ethanoic acid   (2)  ethanol  (3)  propanone  (4)  water

1 link Table H, the lowest vapor pressure has the strongest IMFs
42 At 101.3 kPa and 298 K. what is the total amount of heat released when one mole of aluminum oxide, Al2O3(s), is formed from its elements?

(1) 393.5 kJ  (2) 837.8 kJ   (3) 1676 kJ   (4) 3351 kJ

3 link use table H, find Al2O3 

delta H =-3351kJ

this reaction is for 2 moles, you need 1 mole, so half the amount of energy

43 Given the balanced equation representing a reaction:

What occurred as a result of this reaction?

(1) Energy was absorbed, and entropy increased.

(2) Energy was absorbed, and entropy, decreased

(3) Energy was released, and entropy increased

(4) Energy was released, and entropy decreased.

1 link since energy is a reactants (left side of arrow) it is absorbed

 

entropy is randomness, which increases... liquid to gases

 

44.Given the potential energy diagram representing a reversible reaction;

 

The activation energy for the reverse reaction is represented by

(1) A + B   (2) B + C  (3) B + (4) C + D

2 link go up the hill backwards

B+C

2 link chlorine goes on the 2nd carbon in of a 4 carbon chain

it can start from the right

46 'Which formula represents an unsaturated hydrocarbon?

(1) CH(2) C2H(3) C3H(4) C4H10

2 link use the general formulas on Table Q

unsaturated is not an alkane

not CnH2n+2

 

47 Which ion is most easily reduced?

(l ) Zn2+  (2) Mg2+  (3) Co2+   (4) Ca2+

3 link Table J, reduction is towards the bottom

Oxidation is on top

48 Given the balanced equation representing a reaction:

According to one acid-base theory, the H2O(l) molecules act as

(1) a base because they accept H + ions

(2) a base because they donate H+ ions

(3) an acid because they accept H + ions

(4) an acid because they donate 1-1+ ions

1 link H2O takes an H+ and becomes H3O+

it acts as a base

 

49 Which equation represents an oxidation reduction reaction?

3 link look for oxidation number changing

or find the free element

2 link natural 1 reactant

artificial 2 reactants

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

Question 51 Questions 52-55 Questions 56-59 Questions 60-62 Questions 63-65 Questions 66-68 Questions 69-71 Questions 72-75  Questions 76-78  Questions 79-81  Questions 82-85

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