January 2014 Chemistry Regents #41-50

Highlight to reveal answers and explanations

 

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

Questions 51-54 Questions 55-57 Questions 58-61 Questions 62-63 Questions 64-65 Questions 66-70

Questions 71-75 Questions 76-77 Questions 78-81 Questions 82-85

 

Other Regents Exams

Questions

Answer Links

Explanations

41 Given the potential energy, diagram for a reversible chemical reaction:

Each interval on the axis labeled "Potential Energy (kJ/mol)'" represents 10. kilo joules per mole. What is the activation energy or the forward reaction?

( I ) 10. kJ/mol

(2) 30. kJ/mol

(3) 40. kJ/mol

(4) 60. kJ/mol

3 link The energy to get up the hill.

4 boxes times 10kj/mol

42 Which condensed structural formula  represents an unsaturated compound?

(1) CH3CHCHCH (3) CH3CH3

(2) CH3CH2CH3      (4) CH4

1 link condense the formula to C4H8, it is an alkene, CnH2n,

unsaturated is not all single bonds, alkenes have a double

43 Which element reacts spontaneously with 1.0M HCl (aq) at room temperature?

(1) copper    (3) silver

(2) gold        (4) zinc

4 link table J above H2

 

44 Given the balanced ionic equation:

3Pb2+ + 2Cr ==> 3Pb + 2Cr3+

What is the number of moles of electrons gained by 3.0 moles of lead ions?

(1) 5.0 mol     (3) 3.0 mol

(2) 2.0 mol     (4)  6.0mol

4 link each mole of Pb2+ ions require 2 moles of electrons to reduce

so 2 x 3.0 moles is 6 moles of electrons

 

45 What is the amount of heat energy released when 50.0 grams of water is cooled from 20.0C to 10.0C?

(1) 5.00 X 102 J

(2) 2.09 X I03 J

(3) 1.67 X 105 J

(4) 1.13 X 106 J

2 link Q=mCDT

Q=50.0g x 4.18J/gC x (10-20)

Q=-2090J  (negative is exothermic (energy is released))

46 What occurs at one of the electrodes in both an electrolytic cell and a voltaic c31?

(1) Oxidation occurs  as electrons arc gained at the cathode.

(2) Oxidation occurs as electrons  are lost at the anode.

(3) Reduction occurs as electrons are gained at the anode.

(4) Reduction occurs as electrons are lost at the cathode.

2 link Red Cat An OX

reduction at the cathode, oxidation at the anode

LEO GER

Lose electrons oxidation, gain electrons reduction

 

 

47 Given the balanced equation representing a reaction:

H2O + HCl ==> H3O+ + Cl-

According to one acid-base theory, the H2O molecule

(1)  accepts H+ ions     (3) donate H+ ions

(2) accepts OH- ions (4) donates OH- ions

1 link it accepts H+ and becomes H3O+
48 When an atom of the unstable isotope Na-24 decays, it becomes an atom of Mg-24 because the Na-24 atom spontaneously releases

(1) an alpha particle  (3) a neutron

(2) a beta particle     (4) a positron

2 link  

 

49 Which balanced equation represents nuclear fusion?

3 link 2 Hydrogen's fuse to form Helium

50 Which reaction releases the greatest amount of energy per kilogram of reactants?

1 link the nuclear reaction (fission of Uranium)

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

Questions 51-54 Questions 55-57 Questions 58-61 Questions 62-63 Questions 64-65 Questions 66-70

Questions 71-75 Questions 76-77 Questions 78-81 Questions 82-85

 
Back to Regents Exams