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Physical Setting / Chemistry - New York Regents June 2013 Exam

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Part A
Answer all questions in this part.
   Directions (1–30): For each statement or question, record on your separate answer sheet the number of the
word or expression that, of those given, best completes the statement or answers the question. Some questions
may require the use of the 2011 Edition Reference Tables for Physical Setting/Chemistry.

1.
1 According to the wave-mechanical model of the
  atom, an orbital is a region of the most probable
  location of
  (1) an alpha particle      (3) an electron
  (2) a gamma ray            (4) a proton
Answer: 3

2.
2 Which particles have approximately the same
  mass?
  (1) an electron and an alpha particle
  (2) an electron and a proton
  (3) a neutron and an alpha particle
  (4) a neutron and a proton
Answer: 4

3.
3 During a flame test, a lithium salt produces a
  characteristic red flame. This red color is produced
  when electrons in excited lithium atoms
  (1) are lost by the atoms
  (2) are gained by the atoms
  (3) return to lower energy states within the atoms
  (4) move to higher energy states within the atoms
Answer: 3


4.
4 Compared to the energy and charge of the
  electrons in the first shell of a Be atom, the
  electrons in the second shell of this atom have
  (1) less energy and the same charge
  (2) less energy and a different charge
  (3) more energy and the same charge
  (4) more energy and a different charge
Answer: 3

5.
5 Which quantity can vary among atoms of the
  same element?
  (1) mass number
  (2) atomic number
  (3) number of protons
  (4) number of electrons
Answer: 1

6.
6 Which substances have atoms of the same
  element but different molecular structures?
  (1) He(g) and Ne(g)     (3) K(s) and Na(s)
  (2) O2(g) and O3(g)     (4) P4(s) and S8(s)
Answer: 2

7.
7 An atom that has 13 protons and 15 neutrons is
  an isotope of the element
  (1) nickel               (3) aluminum
  (2) silicon              (4) phosphorus
Answer: 3

8.
8 Which elements have the most similar chemical
  properties?
  (1) Si, As, and Te     (3) Mg, Sr, and Ba
  (2) N2, O2, and F2     (4) Ca, Cs, and Cu
Answer: 3

9.
9 Which list includes three types of chemical
  formulas for organic compounds?
  (1) covalent, metallic, isotopic
  (2) covalent, metallic, molecular
  (3) empirical, structural, isotopic
  (4) empirical, structural, molecular
Answer: 4

10.
10 In a bond between an atom of carbon and an
   atom of fluorine, the fluorine atom has a
   (1) weaker attraction for electrons
   (2) stronger attraction for electrons
   (3) smaller number of first-shell electrons
   (4) larger number of first-shell electrons
Answer: 2

11.
11 A sample of CO2(s) and a sample of CO2(g)
   differ in their
   (1) chemical compositions
   (2) empirical formulas
   (3) molecular structures
   (4) physical properties
Answer: 4

12.
12 Which statement defines the temperature of a
   sample of matter?
   (1) Temperature is a measure of the total
       electromagnetic energy of the particles.
   (2) Temperature is a measure of the total
       thermal energy of the particles.
   (3) Temperature is a measure of the average
       potential energy of the particles.
   (4) Temperature is a measure of the average
       kinetic energy of the particles.
Answer: 4

13.
13 For a chemical reaction, the difference between
   the potential energy of the products and the
   potential energy of the reactants is equal to the
   (1) heat of fusion
   (2) heat of reaction
   (3) activation energy of the forward reaction
   (4) activation energy of the reverse reaction
Answer: 2

14.
14 Which equation represents sublimation?
   (1) Hg(ℓ) → Hg(s)      (3) NH3(g) → NH3(ℓ)
   (2) H2O(s) → H2O(g)     (4) CH4(ℓ) → CH4(g)
Answer: 2

15.
15 Which statement describes the particles of an
   ideal gas, based on the kinetic molecular theory?
   (1) The motion of the gas particles is orderly
       and circular.
   (2) The gas particles have no attractive forces
       between them.
   (3) The gas particles are larger than the dis-
       tances separating them.
   (4) As the gas particles collide, the total energy
       of the system decreases.
Answer: 2

16.
16 Two grams of potassium chloride are completely
   dissolved in a sample of water in a beaker. This
   solution is classified as
   (1) an element
   (2) a compound
   (3) a homogeneous mixture
   (4) a heterogeneous mixture
Answer: 3

17.
17 Which compound has the strongest hydrogen
   bonding between its molecules?
   (1) HBr                (3) HF
   (2) HCl                (4) HI
Answer: 3

18.
18 Powdered sulfur is yellow, and powdered iron is
   gray. When powdered sulfur and powdered iron
   are mixed at 20°C, the powdered iron
   (1) becomes yellow       (3) remains ionic
   (2) becomes a liquid     (4) remains magnetic
Answer: 4

19.
19 An effective collision between reactant particles
   requires the particles to have the proper
   (1) charge and mass
   (2) charge and orientation
   (3) energy and mass
   (4) energy and orientation
Answer: 4

20.
20 Which term is defined as a measure of the
   disorder of a system?
   (1) heat              (3) kinetic energy
   (2) entropy           (4) activation energy
Answer: 2

21.
21 Which process is used to determine the concen-
   tration of an acid?
   (1) chromatography       (3) electrolysis
   (2) distillation         (4) titration
Answer: 4

22.
22 The compounds CH3OCH3 and CH3CH2OH
   have different functional groups. Therefore, these
   compounds have different
   (1) chemical properties
   (2) gram-formula masses
   (3) percent compositions by mass
   (4) numbers of atoms per molecule
Answer: 1

23.
23 Which term identifies the half-reaction that
   occurs at the anode of an operating electro-
   chemical cell?
   (1) oxidation          (3)   neutralization
   (2) reduction          (4)   transmutation
Answer: 1

24.
24 During the operation of a voltaic cell, the cell
   produces
   (1) electrical energy spontaneously
   (2) chemical energy spontaneously
   (3) electrical energy nonspontaneously
   (4) chemical energy nonspontaneously
Answer: 1

25.
25 In which type of chemical reaction are electrons
   transferred?
   (1) organic addition
   (2) oxidation-reduction
   (3) double replacement
   (4) acid-base neutralization
Answer: 2

26.
26 A substance that dissolves in water and produces
   hydronium ions as the only positive ions in the
   solution is classified as
   (1) an alcohol            (3) a base
   (2) an acid               (4) a salt
Answer: 2

27.
27 According to one acid-base theory, a base is an
   (1) H+ acceptor         (3) Na+ acceptor
   (2) H+ donor            (4) Na+ donor
Answer: 1

28.
28 Which compound is an electrolyte?
   (1) CCl4              (3) C6H12O6
   (2) CH3OH             (4) Ca(OH)2
Answer: 4

29.
29 Which term identifies a type of nuclear reaction?
   (1) fermentation          (3) reduction
   (2) deposition            (4) fission
Answer: 4

30.
30 Which radioisotopes have the same decay mode
   and have half-lives greater than 1 hour?
   (1) Au-198 and N-16       (3) I-131 and P-32
   (2) Ca-37 and Fe-53       (4) Tc-99 and U-233
Answer: 3


Part B–1
Answer all questions in this part.
   Directions (31–50): For each statement or question, record on your separate answer sheet the number of the
word or expression that, of those given, best completes the statement or answers the question. Some questions
may require the use of the 2011 Edition Reference Tables for Physical Setting/Chemistry.

31.
31 The diagram below represents the bright-line spectra of four elements and a bright-line spectrum
   produced by a mixture of three of these elements.
                                           Bright-Line Spectra
Which element is not present in the mixture?
(1) A                                      (3) X
(2) D                                      (4) Z
Answer: 3

32.
32 What is the overall charge of an ion that has
   12 protons, 10 electrons, and 14 neutrons?
   (1) 2-                    (3) 4-
   (2) 2+                    (4) 4+
Answer: 2

33.
33 As the elements in Period 3 are considered in
   order of increasing atomic number, there is a
   general decrease in
   (1) atomic mass
   (2) atomic radius
   (3) electronegativity
   (4) first ionization energy
Answer: 2

34.
34 Which electron configuration represents the
   electrons of a sulfur atom in an excited state?
   (1) 2-6-6                 (3) 2-8-4
   (2) 2-7-7                 (4) 2-8-6
Answer: 2

35.
35 Given the word equation:
    sodium chlorate → sodium chloride + oxygen
   Which type of chemical reaction is represented
   by this equation?
   (1) double replacement (3) decomposition
   (2) single replacement (4) synthesis
Answer: 3

36.
36 Which compound has the highest percent com-
   position by mass of strontium?
   (1) SrCl2                 (3) SrO
   (2) SrI2                  (4) SrS
Answer: 3

37.
37 Given the formula for hydrazine:
How many pairs of electrons are shared
between the two nitrogen atoms?
(1) 1                   (3) 3
(2) 2                   (4) 4
Answer: 1

38.
38 Which formulas represent one ionic compound
   and one molecular compound?
   (1) N2 and SO2         (3) BaCl2 and N2O4
   (2) Cl2 and H2S        (4) NaOH and BaSO4
Answer: 3

39.
39 Which Kelvin temperature is equal to 200.°C?
   (1) -73 K              (3) 200. K
   (2) 73 K               (4) 473 K
Answer: 4

40.
40 A 10.0-gram sample of H2O(ℓ) at 23.0°C
   absorbs 209 joules of heat. What is the final
   temperature of the H2O(ℓ) sample?
   (1) 5.0°C              (3) 28.0°C
   (2) 18.0°C             (4) 50.0°C
Answer: 3

41.
41 Given the equation representing a system at
   equilibrium:
When the concentration of Cl-(aq) is increased,
the concentration of Ag+(aq)
(1) decreases, and the amount of AgCl(s) increases
(2) decreases, and the amount of AgCl(s) decreases
(3) increases, and the amount of AgCl(s) increases
(4) increases, and the amount of AgCl(s) decreases
Answer: 1

42.
42 Which particle diagram represents a sample of
   matter that can not be broken down by chemical
   means?

Answer: 4

43.
43 Which formula represents an unsaturated
   hydrocarbon?

Answer: 2

44.
44 When the pH of a solution is changed from 4 to 3,
   the hydronium ion concentration of the solution
   (1) decreases by a factor of 10
   (2) increases by a factor of 10
   (3) decreases by a factor of 100
   (4) increases by a factor of 100
Answer: 2

45.
45 Three samples of the same solution are tested,
   each with a different indicator. All three indicators,
   bromthymol blue, bromcresol green, and thymol
   blue, appear blue if the pH of the solution is
   (1) 4.7                     (3) 7.8
   (2) 6.0                     (4) 9.9
Answer: 4

46.
46 A 10.0-milliliter sample of NaOH(aq) is neutral-
   ized by 40.0 milliliters of 0.50 M HCl. What is
   the molarity of the NaOH(aq)?
   (1) 1.0 M                  (3) 0.25 M
   (2) 2.0 M                  (4) 0.50 M
Answer: 2

47.
47 Radiation is spontaneously emitted from
   hydrogen-3 nuclei, but radiation is not
   spontaneously emitted from hydrogen-1 nuclei
   or hydrogen-2 nuclei. Which hydrogen nuclei
   are stable?
   (1) nuclei of H-1 and H-2, only
   (2) nuclei of H-1 and H-3, only
   (3) nuclei of H-2 and H-3, only
   (4) nuclei of H-1, H-2, and H-3
Answer: 1

48.
48 Given the equation representing a nuclear
   reaction in which X represents a nuclide:

Answer: 2

49.
  49 After decaying for 48 hours, 1/16 of the original
   mass of a radioisotope sample remains unchanged.
   What is the half-life of this radioisotope?
   (1) 3.0 h                   (3) 12 h
   (2) 9.6 h                   (4) 24 h
Answer: 3

50.
50 Which balanced equation represents nuclear
   fusion?

Answer: 1


Part B–2
Answer all questions in this part.
   Directions (51–65): Record your answers in the spaces provided in your answer booklet. Some questions
may require the use of the 2011 Edition Reference Tables for Physical Setting/Chemistry.

51.
Base your answers to questions 51 through 53 on the information below and on your knowledge of chemistry.
          When magnesium is ignited in air, the magnesium reacts with oxygen and nitrogen.
      The reaction between magnesium and nitrogen is represented by the unbalanced equation
      below.
                                  Mg(s) + N2(g) → Mg3N2(s)
      51 Balance the equation in your answer booklet for the reaction between magnesium and
         nitrogen, using the smallest whole-number coefficients. [1]
Answer: MODEL ANSWER GIVEN BELOW
 Allow 1 credit for _______
                           3 Mg(s) + _______ N2(g) → _______ Mg3N2(s).
        Allow credit even if the coefficient “1” is written in front of N2(g) and/or Mg3N2(s).


52.
52 In the ground state, which noble gas has atoms with the same electron configuration as
   a magnesium ion? [1]
Answer: MODEL ANSWER GIVEN BELOW
 Allow 1 credit for Ne or neon.


53.
53 Explain, in terms of electrons, why an atom of the metal in this reaction forms an ion
   that has a smaller radius than its atom. [1]
Answer: MODEL ANSWER GIVEN BELOW
 Allow 1 credit. Acceptable responses include, but are not limited to:
             An atom of magnesium loses its outer shell electrons to form the Mg2+ ion.
             The electron configuration of a magnesium atom is 2-8-2, and the electron configuration of the
             magnesium ion is 2-8.
             An atom of the metal loses electrons to form the ion.


54.
Base your answers to questions 54 through 56 on the information below and on your knowledge of chemistry.
         The balanced equation below represents a reaction.
                                  O2(g) + energy → O(g) + O(g)
      54 Identify the type of chemical bond in a molecule of the reactant. [1]
Answer: MODEL ANSWER GIVEN BELOW
 Allow 1 credit. Acceptable responses include, but are not limited to:
             covalent
             double covalent
             nonpolar
             double


55.
55 In the space in your answer booklet, draw a Lewis electron-dot diagram of one oxygen
   atom. [1]
Answer: MODEL ANSWER GIVEN BELOW
55 [1] Allow 1 credit.
        Examples of 1-credit responses:


56.
56 Explain, in terms of bonds, why energy is absorbed during this reaction. [1]
Answer: MODEL ANSWER GIVEN BELOW
 Allow 1 credit. Acceptable responses include, but are not limited to:
             Energy is needed to break the bonds in O2.


57.
Base your answers to questions 57 through 59 on the information below and on your knowledge of chemistry.
          Starting as a solid at -25°C, a sample of H2O is heated at a constant rate until the
      sample is at 125°C. This heating occurs at standard pressure. The graph below represents
      the relationship between temperature and heat added to the sample.
                                          Heating Curve for H2O
57 Describe what happens to both the potential energy and the average kinetic energy of
   the molecules in the H2O sample during interval AB. [1]
Answer: MODEL ANSWER GIVEN BELOW
 Allow 1 credit. Acceptable responses include, but are not limited to:
             The potential energy remains the same, but the average kinetic energy of the H2O molecules
             increases.
             There is no change in potential energy. There is an increase in the average kinetic energy.


58.
58 Using the graph, determine the total amount of heat added to the sample during
   interval CD. [1]
Answer: MODEL ANSWER GIVEN BELOW
 Allow 1 credit for 8 kJ ± 1 kJ.


59.
59 Explain, in terms of heat of fusion and heat of vaporization, why the heat added during
   interval DE is greater than the heat added during interval BC for this sample of water. [1]
Answer: MODEL ANSWER GIVEN BELOW
 Allow 1 credit. Acceptable responses include, but are not limited to:
             The heat of vaporization of water is 2260 J/g and the heat of fusion for water is only
             334 J/g.
             The heat of fusion of water is much less than its heat of vaporization.


60.
Base your answers to questions 60 through 62 on the information below and on your knowledge of chemistry.
         Cylinder A has a movable piston and contains hydrogen gas. An identical cylinder, B,
      contains methane gas. The diagram below represents these cylinders and the conditions of
      pressure, volume, and temperature of the gas in each cylinder.
60 Compare the total number of gas molecules in cylinder A to the total number of gas
   molecules in cylinder B. [1]
Answer: MODEL ANSWER GIVEN BELOW
 Allow 1 credit. Acceptable responses include, but are not limited to:
             The number of gas molecules in cylinder A is the same as the number of gas molecules
             in cylinder B.


61.
61 State a change in temperature and a change in pressure that will cause the gas in
   cylinder A to behave more like an ideal gas. [1]
Answer: MODEL ANSWER GIVEN BELOW
 Allow 1 credit. Acceptable responses include, but are not limited to:
             Temperature: above 293 K
             Pressure: below 1.2 atm
             Temperature: higher
             Pressure: lower


62.
62 In the space in your answer booklet, show a numerical setup for calculating the volume
   of the gas in cylinder B at STP. [1]
Answer: MODEL ANSWER GIVEN BELOW
62 [1] Allow 1 credit. Acceptable responses include, but are not limited to:


63.
Base your answers to questions 63 through 65 on the information below and on your knowledge of chemistry.
          There are several isomers of C6H14. The formulas and boiling points for two of these
      isomers are given in the table below.
63 Identify the homologous series to which these isomers belong. [1]
Answer: MODEL ANSWER GIVEN BELOW
 Allow 1 credit. Acceptable responses include, but are not limited to:
             alkanes
             CnH2n+2


64.
64 Write the empirical formula for isomer 1. [1]
Answer: MODEL ANSWER GIVEN BELOW
 Allow 1 credit for C3H7. The order of the elements can vary.


65.
65 Explain, in terms of intermolecular forces, why isomer 2 boils at a lower temperature
   than isomer 1. [1]
Answer: MODEL ANSWER GIVEN BELOW
 Allow 1 credit. Acceptable responses include, but are not limited to:
             Isomer 2 boils at a lower temperature because it has weaker intermolecular forces than isomer 1.
             The intermolecular forces in isomer 1 are stronger.



Part C
Answer all questions in this part.
   Directions (66–85): Record your answers in the spaces provided in your answer booklet. Some questions
may require the use of the 2011 Edition Reference Tables for Physical Setting/Chemistry.

66.
Base your answers to questions 66 through 69 on the information below and on your knowledge of chemistry.
          Before atomic numbers were known, Mendeleev developed a classification system for
      the 63 elements known in 1872, using oxide formulas and atomic masses. He used an R in
      the oxide formulas to represent any element in each group. The atomic mass was listed in
      parentheses after the symbol of each element. A modified version of Mendeleev’s classification
      system is shown in the table below.
                             Modified Version of Mendeleev’s Table
66 Identify one characteristic used by Mendeleev to develop his classification system of the
   elements. [1]
Answer: MODEL ANSWER GIVEN BELOW
66 [1] Allow 1 credit. Acceptable responses include, but are not limited to:
             increasing atomic mass
             atomic mass
             oxide formulas


67.
67 Based on Mendeleev’s oxide formula, what is the number of electrons lost by each atom
   of the elements in Group III? [1]
Answer: MODEL ANSWER GIVEN BELOW
67 [1] Allow 1 credit. Acceptable responses include, but are not limited to:
             three electrons
             three
             3


68.
68 Based on Table J, identify the least active metal listed in Group I on Mendeleev’s table. [1]
Answer: MODEL ANSWER GIVEN BELOW
68 [1] Allow 1 credit. Acceptable responses include, but are not limited to:
             Ag
             silver


69.
69 Explain, in terms of chemical reactivity, why the elements in Group 18 on the modern
   Periodic Table were not identified by Mendeleev at that time. [1]
Answer: MODEL ANSWER GIVEN BELOW
69 [1] Allow 1 credit. Acceptable responses include, but are not limited to:
             Since the Group 18 elements tend not to react with other elements, there were no
             oxide compounds for Mendeleev to study.
             Group 18 elements are generally unreactive.


70.
Base your answers to questions 70 through 73 on the information below and on your knowledge of chemistry.
          In a laboratory apparatus, a sample of lead(II) oxide reacts with hydrogen gas at high
      temperature. The products of this reaction are liquid lead and water vapor. As the reaction
      proceeds, water vapor and excess hydrogen gas leave the glass tube. The diagram and
      balanced equation below represent this reaction.
                   PbO(s) + H2(g) + heat →  Pb(ℓ) + H2O(g)
70 Determine the change in oxidation number for the hydrogen that reacts. [1]
Answer: MODEL ANSWER GIVEN BELOW
70 [1] Allow 1 credit. Acceptable responses include, but are not limited to:
             From 0 to +1
             From zero to one


71.
71 Write a balanced half-reaction equation for the reduction of the Pb2+ ions in this
   reaction. [1]
Answer: MODEL ANSWER GIVEN BELOW
71 [1] Allow 1 credit. Acceptable responses include, but are not limited to:
             Pb2+ + 2e- → Pb


72.
72 Explain why the reaction that occurs in this glass tube can not reach equilibrium. [1]
Answer: MODEL ANSWER GIVEN BELOW
72 [1] Allow 1 credit. Acceptable responses include, but are not limited to:
             The glass tube is not a closed system.
             Gases are entering and leaving the system.
             The reaction is not reversible under these conditions.


73.
73 State one change in reaction conditions, other than adding a catalyst, that would cause
   the rate of this reaction to increase. [1]
Answer: MODEL ANSWER GIVEN BELOW
 Allow 1 credit. Acceptable responses include, but are not limited to:
             Increase the temperature.
             Increase the concentration of the hydrogen gas in the tube.
             Grind the metal oxide to increase its surface area.


74.
Base your answers to questions 74 through 77 on the information below and on your knowledge of chemistry.
          In the late 19th century, the Hall-Herroult process was invented as an inexpensive way
      to produce aluminum. In this process, Al2O3(ℓ) extracted from bauxite is dissolved in
      Na3AlF6(ℓ) in a graphite-lined tank, as shown in the diagram below. The products are
      carbon dioxide and molten aluminum metal.
74 Compare the chemical properties of a 300.-kilogram sample of Al2O3(ℓ) with the
   chemical properties of a 600.-kilogram sample of Al2O3(ℓ). [1]
Answer: MODEL ANSWER GIVEN BELOW
 Allow 1 credit. Acceptable responses include, but are not limited to:
             Both samples have the same chemical properties.


75.
75 Write the chemical name for the liquid compound dissolved in the Na3AlF6(ℓ). [1]
Answer: MODEL ANSWER GIVEN BELOW
 Allow 1 credit. Acceptable responses include, but are not limited to:
             aluminum oxide


76.
76 What is the melting point of the substance that collects at the bottom of the tank? [1]
Answer: MODEL ANSWER GIVEN BELOW
 Allow 1 credit for 933 K.


77.
77 Compare the density of the Al(ℓ) with the density of the mixture of Al2O3(ℓ) and
   Na3AlF6(ℓ). [1]
Answer: MODEL ANSWER GIVEN BELOW
 Allow 1 credit. Acceptable responses include, but are not limited to:
             The density of the aluminum is greater than the density of the Al2O3 and Na3AlF6 mixture.
             The density of Al(ℓ) is greater.


78.
Base your answers to questions 78 through 80 on the information below and on your knowledge of chemistry.
          One process used to manufacture sulfuric acid is called the contact process. One step
      in this process, the reaction between sulfur dioxide and oxygen, is represented by the
      forward reaction in the system at equilibrium shown below.
                               2SO2(g) + O2(g) ⇌ 2SO3(g) + 394 kJ
          A mixture of platinum and vanadium(V) oxide may be used as a catalyst for this
      reaction. The sulfur trioxide produced is then used to make sulfuric acid.
      78 Determine the amount of energy released when 1.00 mole of sulfur trioxide is
         produced. [1]
Answer: MODEL ANSWER GIVEN BELOW
 Allow 1 credit for 197 kJ.


79.
79 Write the chemical formula for vanadium(V) oxide. [1]
Answer: MODEL ANSWER GIVEN BELOW
 Allow 1 credit. Acceptable responses include, but are not limited to:
             V2O5
             O5V2


80.
80 On the labeled axes in your answer booklet, complete the potential energy diagram for
   the forward reaction represented by this equation. [1]
Answer: MODEL ANSWER GIVEN BELOW
80 [1] Allow 1 credit.
        Example of a 1-credit response:


81.
Base your answers to questions 81 and 82 on the information below and on your knowledge of chemistry.
         Two very stable compounds, Freon-12 and Freon-14, are used as liquid refrigerants. A
      Freon-12 molecule consists of one carbon atom, two chlorine atoms, and two fluorine
      atoms. A Freon-14 molecule consists of one carbon atom and four fluorine atoms.
      81 In the space in your answer booklet, draw a structural formula for Freon-12. [1]
Answer: MODEL ANSWER GIVEN BELOW
81 [1] Allow 1 credit.
        Examples of 1-credit responses:


82.
82 To which class of organic compounds do Freon-12 and Freon-14 belong? [1]
Answer: MODEL ANSWER GIVEN BELOW
 Allow 1 credit. Acceptable responses include, but are not limited to:
             halide
             halocarbon


83.
Base your answers to questions 83 through 85 on the information below and on your knowledge of chemistry.
          Chemical concepts are applied in candy making. A recipe for making lollipops is shown
      below.
                                   Hard-Candy Lollipops Recipe
         Ingredients:
         414 grams of sugar
         177 grams of water
         158 milliliters of light corn syrup
         Step 1: In a saucepan, mix the sugar and water. Heat this mixture, while stirring, until
                 all of the sugar dissolves.
         Step 2: Add the corn syrup and heat the mixture until it boils.
         Step 3: Continue boiling the mixture until the temperature reaches 143°C at standard
                 pressure.
         Step 4: Remove the pan from the heat and allow it to stand until the bubbling stops.
                 Pour the mixture into lollipop molds that have been coated with cooking oil
                 spray.
      83 Explain, in terms of the polarity of sugar molecules, why the sugar dissolves in water. [1]
Answer: MODEL ANSWER GIVEN BELOW
 Allow 1 credit. Acceptable responses include, but are not limited to:
             The polarity of sugar molecules is similar to the polarity of water molecules.
             Both substances consist of polar molecules.


84.
84 Determine the concentration, expressed as percent by mass, of the sugar dissolved in
   the mixture produced in step 1. [1]
Answer: MODEL ANSWER GIVEN BELOW
 Allow 1 credit for 70.1%. Significant figures do not need to be shown.


85.
85 Explain, in terms of the concentration of sugar molecules, why the boiling point of the
   mixture in step 3 increases as water evaporates from the mixture. [1]
Answer: MODEL ANSWER GIVEN BELOW
 Allow 1 credit. Acceptable responses include, but are not limited to:
             The boiling point of the mixture increases as water evaporates because the concentration of
             dissolved molecules increases.
             An increase in the concentration of sugar particles increases the boiling point.



  Try the Quiz :     Physical Setting / Chemistry - New York Regents June 2013 Exam


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