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Physical Setting / Chemistry - New York Regents January 2012 Exam

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Part A
Answer all questions in this part.
   Directions (1–30): For each statement or question, write in your answer booklet 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 Reference Tables for Physical Setting/Chemistry.

1.
1 What is the number of electrons in a completely
  filled second shell of an atom?
  (1) 32                     (3) 18
  (2) 2                      (4) 8
Answer: 4

2.
2 What is the number of electrons in an atom that
  has 3 protons and 4 neutrons?
  (1) 1                    (3) 3
  (2) 7                    (4) 4
Answer: 3

3.
3 As a result of the gold foil experiment, it was
  concluded that an atom
  (1) contains protons, neutrons, and electrons
  (2) contains a small, dense nucleus
  (3) has positrons and orbitals
  (4) is a hard, indivisible sphere
Answer: 2


4.
4 Which statement describes the distribution of
  charge in an atom?
  (1) A neutral nucleus is surrounded by one or
      more negatively charged electrons.
  (2) A neutral nucleus is surrounded by one or
      more positively charged electrons.
  (3) A positively charged nucleus is surrounded
      by one or more negatively charged electrons.
  (4) A positively charged nucleus is surrounded
      by one or more positively charged electrons.
Answer: 3

5.
5 Which atom in the ground state has an outer-
  most electron with the most energy?
  (1) Cs                  (3) Li
  (2) K                   (4) Na
Answer: 1

6.
6 Which particle has the least mass?
  (1) alpha particle       (3) neutron
  (2) beta particle        (4) proton
Answer: 2

7.
7 The elements in Group 2 are classified as
  (1) metals             (3) nonmetals
  (2) metalloids         (4) noble gases
Answer: 1

8.
8 Which list includes elements with the most
  similar chemical properties?
  (1) Br, Ga, Hg           (3) O, S, Se
  (2) Cr, Pb, Xe           (4) N, O, F
Answer: 3

9.
9 The notation for the nuclide 13755Cs
                                
  gives information about
  (1) mass number, only
  (2) atomic number, only
  (3) both mass number and atomic number
  (4) neither mass number nor atomic number
Answer: 3

10.
10 Which pair represents two forms of an element
   in the same phase at STP but with different
   structures and different properties?
   (1) I2(s) and I2(g)       (3) H2(g) and Hg(g)
   (2) O2(g) and O3(g)       (4) H2O(s) and H2O(ℓ)
Answer: 2

11.
11 The elements on the Periodic Table are
   arranged in order of increasing
   (1) atomic mass          (3) molar mass
   (2) atomic number        (4) oxidation number
Answer: 2

12.
12 What is the IUPAC name for the compound
   ZnO?
   (1) zinc oxide      (3) zinc peroxide
   (2) zinc oxalate    (4) zinc hydroxide
Answer: 1

13.
13 Which atom attains a stable valence electron
   configuration by bonding with another atom?
   (1) neon                (3) helium
   (2) radon               (4) hydrogen
Answer: 4

14.
14 An ionic bond can be formed when one or more
   electrons are
   (1) equally shared by two atoms
   (2) unequally shared by two atoms
   (3) transferred from the nucleus of one atom to
       the nucleus of another atom
   (4) transferred from the valence shell of one
       atom to the valence shell of another atom
Answer: 4

15.
15 Which sample of CO2 has a definite shape and
   a definite volume?
   (1) CO2(aq)           (3) CO2(ℓ)
   (2) CO2(g)            (4) CO2(s)
Answer: 4

16.
16 What occurs in order to break the bond in a
   Cl2 molecule?
   (1) Energy is absorbed.
   (2) Energy is released.
   (3) The molecule creates energy.
   (4) The molecule destroys energy.
Answer: 1

17.
17 A sealed, rigid 1.0-liter cylinder contains He gas
   at STP. An identical sealed cylinder contains
   Ne gas at STP. These two cylinders contain the
   same number of
   (1) atoms                   (3) ions
   (2) electrons               (4) protons
Answer: 1

18.
18 Which statement describes a chemical change?
   (1) Alcohol evaporates.
   (2) Water vapor forms snowflakes.
   (3) Table salt (NaCl) is crushed into powder.
   (4) Glucose (C6H12O6) and oxygen produce
       CO2 and H2O.
Answer: 4

19.
19 Which statement describes the particles of an
   ideal gas according to the kinetic molecular
   theory?
   (1) The gas particles are arranged in a regular
       geometric pattern.
   (2) The gas particles are in random, constant,
       straight-line motion.
   (3) The gas particles are separated by very small
       distances, relative to their sizes.
   (4) The gas particles are strongly attracted to
       each other.
Answer: 2

20.
20 Which sample of matter is classified as a
   substance?
   (1) air             (3) milk
   (2) ammonia         (4) seawater
Answer: 2

21.
21 Which element has the lowest electronegativity
   value?
   (1) F                  (3) Cl
   (2) Fr                 (4) Cr
Answer: 2

22.
22 At standard pressure, CH4 boils at 112 K and
   H2O boils at 373 K. What accounts for the higher
   boiling point of H2O at standard pressure?
   (1) covalent bonding      (3) hydrogen bonding
   (2) ionic bonding         (4) metallic bonding
Answer: 3

23.
23 A mixture of sand and table salt can be separated
   by filtration because the substances in the
   mixture differ in
   (1) boiling point        (3) freezing point
   (2) density at STP       (4) solubility in water
Answer: 4

24.
24 Systems in nature tend to undergo changes
   toward
   (1) lower energy and lower entropy
   (2) lower energy and higher entropy
   (3) higher energy and lower entropy
   (4) higher energy and higher entropy
Answer: 2

25.
25 In the wave-mechanical model of the atom, an
   orbital is the most probable location of
   (1) a proton              (3) a neutron
   (2) a positron            (4) an electron
Answer: 4

26.
26 Functional groups are used to classify
   (1) organic compounds
   (2) inorganic compounds
   (3) heterogeneous mixtures
   (4) homogeneous mixtures
Answer: 1

27.
27 Which class of compounds contains at least one
   element from Group 17 of the Periodic Table?
   (1) aldehyde           (3) ester
   (2) amine              (4) halide
Answer: 4

28.
28 In a propanal molecule, an oxygen atom is
   bonded with a carbon atom. What is the total
   number of pairs of electrons shared between
   these atoms?
   (1) 1                  (3) 3
   (2) 2                  (4) 4
Answer: 2

29.
29 When a voltaic cell operates, ions move through
   the
   (1) anode                (3) salt bridge
   (2) cathode              (4) external circuit
Answer: 3

30.
30 When dissolved in water, an Arrhenius base
   yields
   (1) hydrogen ions     (3) hydroxide ions
   (2) hydronium ions    (4) oxide ions
Answer: 3


Part B–1
Answer all questions in this part.
    Directions (31–50): For each statement or question, write in your answer booklet 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 Reference Tables for Physical Setting/Chemistry.

31.
31 What is the total number of valence electrons in
   a germanium atom in the ground state?
   (1) 22                   (3) 32
   (2) 2                    (4) 4
Answer: 4

32.
32 Which element is paired with an excited-state
   electron configuration for an atom of the
   element?
   (1) Ca: 2-8-8-2        (3) K: 2-6-8-3
   (2) Na: 2-8-2          (4) F: 2-8
Answer: 3

33.
33 Given the balanced equations representing two
   chemical reactions:
            Cl2 + 2NaBr → 2NaCl + Br2
                 2NaCl → 2Na + Cl2
   Which types of chemical reactions are represented
   by these equations?
   (1) single replacement and decomposition
   (2) single replacement and double replacement
   (3) synthesis and decomposition
   (4) synthesis and double replacement
Answer: 1

34.
34 An ion that consists of 7 protons, 6 neutrons,
   and 10 electrons has a net charge of
   (1) 4−                   (3) 3+
   (2) 3−                   (4) 4+
Answer: 2

35.
35 Which Lewis electron-dot diagram represents a
   molecule having a nonpolar covalent bond?

Answer: 1

36.
36 Which quantity is equal to 50 kilojoules?
   (1) 0.05 J               (3) 5 × 103 J
   (2) 500 J                (4) 5 × 104 J
Answer: 4

37.
37 Which compound is formed from its elements
   by an exothermic reaction at 298 K and
   101.3 kPa?
   (1) C2H4(g)          (3) H2O(g)
   (2) HI(g)            (4) NO2(g)
Answer: 3

38.
38 At which temperature is the vapor pressure of
   ethanol equal to 80. kPa?
   (1) 48°C                 (3) 80.°C
   (2) 73°C                 (4) 101°C
Answer: 2

39.
39 At 25°C, gas in a rigid cylinder with a movable
   piston has a volume of 145 mL and a pressure of
   125 kPa. Then the gas is compressed to a
   volume of 80. mL. What is the new pressure of
   the gas if the temperature is held at 25°C?
   (1) 69 kPa                (3) 160 kPa
   (2) 93 kPa                (4) 230 kPa
Answer: 4

40.
40 A 2400.-gram sample of an aqueous solution
   contains 0.012 gram of NH3. What is the
   concentration of NH3 in the solution, expressed
   as parts per million?
   (1) 5.0 ppm             (3) 20. ppm
   (2) 15 ppm              (4) 50. ppm
Answer: 1

41.
41 Which equation represents a change that results
   in an increase in disorder?
   (1) I2(s) → I2(g)
   (2) CO2(g) → CO2(s)
   (3) 2Na(s) + Cl2(g) → 2NaCl(s)
   (4) 2H2(g) + O2(g) → 2H2O(ℓ)
Answer: 1

42.
42 A solution consists of 0.50 mole of CaCl2
   dissolved in 100. grams of H2O at 25°C.
   Compared to the boiling point and freezing
   point of 100. grams of H2O at standard
   pressure, the solution at standard pressure has
   (1) a lower boiling point and a lower freezing
       point
   (2) a lower boiling point and a higher freezing
       point
   (3) a higher boiling point and a lower freezing
       point
   (4) a higher boiling point and a higher freezing
       point
Answer: 3

43.
43 Given the balanced ionic equation representing
   a reaction:
      2Al(s) + 3Cu2+(aq) → 2Al3+(aq) + 3Cu(s)
   Which half-reaction represents the reduction
   that occurs?
   (1) Al → Al3+ + 3e
   (2) Al3+ + 3e → Al
   (3) Cu → Cu2+ + 2e
   (4) Cu2+ + 2e → Cu
Answer: 4

44.
44 Given the equation and potential energy diagram
   representing a reaction:
If each interval on the axis labeled “Potential
Energy (kJ/mol)” represents 10. kJ/mol, what is
the heat of reaction?
(1) +60. kJ/mol         (3) +30. kJ/mol
(2) +20. kJ/mol         (4) +40. kJ/mol
Answer: 3

45.
45 Some solid KNO3 remains at the bottom of a
   stoppered flask containing a saturated
   KNO3(aq) solution at 22°C. Which statement
   explains why the contents of the flask are at
   equilibrium?
   (1) The rate of dissolving is equal to the rate of
       crystallization.
   (2) The rate of dissolving is greater than the rate
       of crystallization.
   (3) The concentration of the solid is equal to the
       concentration of the solution.
   (4) The concentration of the solid is greater
       than the concentration of the solution.
Answer: 1

46.
46 Which formula represents the product of the
   addition reaction between ethene and chlorine,
   Cl2?

Answer: 2

47.
47 Based on Reference Table J, which two reactants
   react spontaneously?
   (1) Mg(s) + ZnCl2(aq)   (3) Pb(s) + ZnCl2(aq)
   (2) Cu(s) + FeSO4(aq)   (4) Co(s) + NaCl(aq)
Answer: 1

48.
48 When the pH value of a solution is changed from
   2 to 1, the concentration of hydronium ions
   (1) decreases by a factor of 2
   (2) increases by a factor of 2
   (3) decreases by a factor of 10
   (4) increases by a factor of 10
Answer: 4

49.
49 Given the balanced equation representing a
   nuclear reaction:
Which phrase identifies and describes this
reaction?
(1) fission, mass converted to energy
(2) fission, energy converted to mass
(3) fusion, mass converted to energy
(4) fusion, energy converted to mass
Answer: 3

50.
50 Given the equation representing a reversible
   reaction:
      NH3(g) + H2O(ℓ) ⇌ NH4+(aq) + OH (aq)
   According to one acid-base theory, the reactant
   that donates an H+ ion in the forward reaction is
   (1) NH3(g)                (3) NH4+(aq)
   (2) H2O(ℓ)                (4) OH (aq)
Answer: 2


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 Reference Tables for Physical Setting/Chemistry.

51.
Base your answers to questions 51 through 54 on the information below.
          The atomic radius and the ionic radius for some Group 1 and some Group 17 elements
      are given in the tables below.
                           Atomic and Ionic Radii of Some Elements
                              Group 1                         Group 17
                                                             
                      Particle   Radius (pm)        Particle          Radius (pm)
                                                                 
                     Li atom         130.            F atom           60.
                     Li+ ion          78             F ion          133
                     Na atom         160.            Cl atom         100.
                     Na+ ion          98             Cl ion         181
                     K atom          200.            Br atom         117
                     K+ ion          133             Br ion          ?
                     Rb atom         215             l atom          136
                     Rb+ ion         148             l ion          220.
      51 Estimate the radius of a Br ion. [1]
Answer: MODEL ANSWER GIVEN BELOW
 Allow 1 credit for an ionic radius value greater than 181 pm and less than 220. pm.


52.
52 Explain, in terms of electron shells, why the radius of a K+ ion is greater than the radius
   of an Na+ ion. [1]
Answer: MODEL ANSWER GIVEN BELOW
 Allow 1 credit. Acceptable responses include, but are not limited to:
             A K+ ion has three electron shells and an Na+ ion has only two.
             A sodium ion has fewer electron shells than a potassium ion.


53.
53 Write both the name and the charge of the particle that is gained by an F atom when
   the atom becomes an F ion. [1]
Answer: MODEL ANSWER GIVEN BELOW
 Allow 1 credit. Acceptable responses include, but are not limited to:
             Particle: electron
             Charge of particle: −1
             Particle: electron
             Charge of particle: negative


54.
54 State the relationship between atomic number and first ionization energy as the
   elements in Group 1 are considered in order of increasing atomic number. [1]
Answer: MODEL ANSWER GIVEN BELOW
 Allow 1 credit. Acceptable responses include, but are not limited to:
             As the elements in Group 1 are considered in order of increasing atomic number, first
             ionization energy decreases.
             As atomic number increases, first ionization energy decreases.


55.
Base your answers to questions 55 through 57 on the information below.
         Starting as a gas at 206°C, a sample of a substance is allowed to cool for 16 minutes.
      This process is represented by the cooling curve below.
                                    Cooling Curve for a Substance
55 What is the melting point of this substance? [1]
Answer: MODEL ANSWER GIVEN BELOW
 Allow 1 credit for 90°C ± 2°C.


56.
56 At what time do the particles of this sample have the lowest average kinetic energy? [1]
Answer: MODEL ANSWER GIVEN BELOW
 Allow 1 credit. Acceptable responses include, but are not limited to:
             minute 16
             at 16 minutes


57.
57 Using the key in your answer booklet, draw two particle diagrams to represent the
   two phases of the sample at minute 4. Your response must include at least six particles
   for each diagram. [1]
Answer: MODEL ANSWER GIVEN BELOW
57 [1] Allow 1 credit. Particles of the gas must be drawn farther apart than particles of the liquid.
        Example of a 1-credit response:
 


58.
Base your answers to questions 58 and 59 on the information below.
         Two hydrocarbons that are isomers of each other are represented by the structural
      formulas and molecular formulas below.
58 Explain, in terms of bonds, why these hydrocarbons are unsaturated. [1]
Answer: MODEL ANSWER GIVEN BELOW
 Allow 1 credit. Acceptable responses include, but are not limited to:
             A hydrocarbon 1 molecule has two carbon-carbon double bonds and a hydrocarbon 2 molecule
             has one carbon-carbon triple bond.
             Both hydrocarbons have at least one multiple covalent bond between two carbon atoms.


59.
59 Explain, in terms of structural formulas and molecular formulas, why these hydrocarbons
   are isomers of each other. [1]
Answer: MODEL ANSWER GIVEN BELOW
 Allow 1 credit. Acceptable responses include, but are not limited to:
             The molecular formulas of the two hydrocarbons are the same, but the structural formulas are
             different.


60.
Base your answers to questions 60 through 62 on the information below.
          The diagram below represents an operating electrolytic cell used to plate silver onto a
      nickel key. As the cell operates, oxidation occurs at the silver electrode and the mass of the
      silver electrode decreases.
60 Identify the cathode in the cell. [1]
Answer: MODEL ANSWER GIVEN BELOW
 Allow 1 credit. Acceptable responses include, but are not limited to:
             Ni(s) key
             key
             nickel


61.
61 State the purpose of the power source in the cell. [1]
Answer: MODEL ANSWER GIVEN BELOW
 Allow 1 credit. Acceptable responses include, but are not limited to:
             The cell requires electrical energy for the nonspontaneous reaction to occur.
             The power source causes some Ag(s) atoms to oxidize.


62.
62 Explain, in terms of Ag atoms and Ag+(aq) ions, why the mass of the silver electrode
   decreases as the cell operates. [1]
Answer: MODEL ANSWER GIVEN BELOW
 Allow 1 credit. Acceptable responses include, but are not limited to:
             Silver atoms lose electrons and become silver ions in the solution.
             Some of the Ag atoms become Ag+ ions.
             Silver atoms are oxidized to silver ions.


63.
Base your answers to questions 63 through 65 on the information below.
          In a titration, a few drops of an indicator are added to a flask containing 35.0 milliliters
      of HNO3(aq) of unknown concentration. After 30.0 milliliters of 0.15 M NaOH(aq)
      solution is slowly added to the flask, the indicator changes color, showing the acid is
      neutralized.
      63 The volume of the NaOH(aq) solution is expressed to what number of significant
         figures? [1]
Answer: MODEL ANSWER GIVEN BELOW
 Allow 1 credit for 3 or three.


64.
64 Complete the equation in your answer booklet for this neutralization reaction by
   writing the formula of each product. [1]
Answer: MODEL ANSWER GIVEN BELOW
 Allow 1 credit. Acceptable responses include, but are not limited to:
             NaNO3(aq) + H2O(ℓ )
             HOH + NaNO3


65.
65 In the space in your answer booklet, show a numerical setup for calculating the
   concentration of the HNO3(aq) solution. [1]
Answer: MODEL ANSWER GIVEN BELOW
65 [1] Allow 1 credit. Acceptable responses include, but are not limited to:
             MA(35.0 mL) = (0.15 M)(30.0 mL)
             0.15 × 30 / 35
   



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 Reference Tables for Physical Setting/Chemistry.

66.
Base your answers to questions 66 through 69 on the information below.
          During a fireworks display, salts are heated to very high temperatures. Ions in the salts
      absorb energy and become excited. Spectacular colors are produced as energy is emitted
      from the ions in the form of light.
          The color of the emitted light is characteristic of the metal ion in each salt.
      For example, the lithium ion in lithium carbonate, Li2CO3, produces a deep-red color.
      The strontium ion in strontium carbonate, SrCO3, produces a bright-red color. Similarly,
      calcium chloride is used for orange light, sodium chloride for yellow light, and barium
      chloride for green light.
      66 Write the formula for the salt used to produce green light in a fireworks display. [1]
Answer: MODEL ANSWER GIVEN BELOW
 Allow 1 credit for BaCl2.


67.
67 Identify the two types of chemical bonds found in the salt used to produce a deep-red
   color. [1]
Answer: MODEL ANSWER GIVEN BELOW
 Allow 1 credit. Acceptable responses include, but are not limited to:
             ionic bonds and polar covalent bonds
             covalent and ionic


68.
68 Determine the oxidation state of carbon in the salt used to produce a bright-red color. [1]
Answer: MODEL ANSWER GIVEN BELOW
 Allow 1 credit for +4.


69.
69 Explain, in terms of subatomic particles and energy states, how the colors in a
   fireworks display are produced. [1]
Answer: MODEL ANSWER GIVEN BELOW
 Allow 1 credit. Acceptable responses include, but are not limited to:
             When electrons in the ions move from higher energy states to lower energy states, lights of
             specific wavelengths are emitted.
             Light is emitted when electrons return from higher electron shells to lower electron shells.


70.
Base your answers to questions 70 and 71 on the information below.
          A scientist makes a solution that contains 44.0 grams of hydrogen chloride gas, HCl(g),
      in 200. grams of water, H2O(ℓ), at 20.°C. This process is represented by the balanced
      equation below.
70 Based on Reference Table G, identify, in terms of saturation, the type of solution made
   by the scientist. [1]
Answer: MODEL ANSWER GIVEN BELOW
 Allow 1 credit. Acceptable responses include, but are not limited to:
             unsaturated solution
             unsaturated


71.
71 Explain, in terms of the distribution of particles, why the solution is a homogeneous
   mixture. [1]
Answer: MODEL ANSWER GIVEN BELOW
 Allow 1 credit. Acceptable responses include, but are not limited to:
             The H+ ions and the Cl ions are distributed uniformly throughout the solution.
             There is an even distribution of H+(aq) and Cl(aq).


72.
Base your answers to questions 72 through 74 on the information below.
          Iron has been used for thousands of years. In the air, iron corrodes. One reaction for the
      corrosion of iron is represented by the balanced equation below.
                              Equation 1: 4Fe(s) + 3O2(g) → 2Fe2O3(s)
          In the presence of water, iron corrodes more quickly. This corrosion is represented by
      the unbalanced equation below.
                          Equation 2: Fe(s) + O2(g) + H2O(ℓ) → Fe(OH)2(s)
      72 Identify one substance in the passage that can not be broken down by a chemical
         change. [1]
Answer: MODEL ANSWER GIVEN BELOW
 Allow 1 credit. Acceptable responses include, but are not limited to:
             Fe
             oxygen


73.
73 Using equation 1, describe one chemical property of iron. [1]
Answer: MODEL ANSWER GIVEN BELOW
 Allow 1 credit. Acceptable responses include, but are not limited to:
             Iron reacts with oxygen to form a compound.
             An iron atom can lose three electrons.
             The Fe atoms can form positive ions.


74.
74 Balance the equation in your answer booklet, using the smallest whole-number
   coefficients. [1]
Answer: MODEL ANSWER GIVEN BELOW
 Allow 1 credit for  2  Fe(s) + _______O2(g) +  2  H2O(ℓ) →  2  Fe(OH)2(s).
        Allow credit even if the coefficient “1” is written in front of O2(g).


75.
Base your answers to questions 75 through 78 on the information below.
          Vitamin C, also known as ascorbic acid, is water soluble and cannot be produced by
      the human body. Each day, a person’s diet should include a source of vitamin C, such as
      orange juice. Ascorbic acid has a molecular formula of C6H8O6 and a gram-formula mass of
      176 grams per mole.
      75 What is the color of the indicator thymol blue after it is added to an aqueous solution
         of vitamin C? [1]
Answer: MODEL ANSWER GIVEN BELOW
 Allow 1 credit for yellow.


76.
76 Determine the number of moles of vitamin C in an orange that contains 0.071 gram of
   vitamin C. [1]
Answer: MODEL ANSWER GIVEN BELOW
 Allow 1 credit. Significant figures do not need to be shown. Acceptable responses include, but are
       not limited to:
             4.0 × 10−4 mol
             0.000 40 mol


77.
77 In the space in your answer booklet, show a numerical setup for calculating the percent
   composition by mass of oxygen in ascorbic acid. [1]
Answer: MODEL ANSWER GIVEN BELOW
77 [1] Allow 1 credit. Acceptable responses include, but are not limited to:


78.
78 Write the empirical formula for ascorbic acid. [1]
Answer: MODEL ANSWER GIVEN BELOW
 Allow 1 credit for C3H4O3. The order of the elements can vary.


79.
Base your answers to questions 79 through 81 on the information below.
          Several steps are involved in the industrial production of sulfuric acid. One step
      involves the oxidation of sulfur dioxide gas to form sulfur trioxide gas. A catalyst is used to
      increase the rate of production of sulfur trioxide gas. In a rigid cylinder with a movable
      piston, this reaction reaches equilibrium, as represented by the equation below.
                                  2SO2(g) + O2(g) ⇌ 2SO3(g) + 392 kJ
      79 Explain, in terms of collision theory, why increasing the pressure of the gases in the
         cylinder increases the rate of the forward reaction. [1]
Answer: MODEL ANSWER GIVEN BELOW
 Allow 1 credit. Acceptable responses include, but are not limited to:
             When the pressure in the cylinder is increased, the SO2(g) molecules and O2(g) molecules
             collide more frequently, producing more SO3(g).


80.
80 Determine the amount of heat released by the production of 1.0 mole of SO3(g). [1]
Answer: MODEL ANSWER GIVEN BELOW
 Allow 1 credit for 196 kJ.


81.
81 State, in terms of the concentration of SO3(g), what occurs when more O2(g) is added
   to the reaction at equilibrium. [1]
Answer: MODEL ANSWER GIVEN BELOW
 Allow 1 credit. Acceptable responses include, but are not limited to:
             The concentration of SO3(g) increases.


82.
Base your answers to questions 82 through 85 on the information below.
          Nuclear radiation is harmful to living cells, particularly to fast-growing cells, such as
      cancer cells and blood cells. An external beam of the radiation emitted from a radioisotope
      can be directed on a small area of a person to destroy cancer cells within the body.
          Cobalt-60 is an artificially produced radioisotope that emits gamma rays and beta
      particles. One hospital keeps a 100.0-gram sample of cobalt-60 in an appropriate, secure
      storage container for future cancer treatment.
      82 State one risk to human tissue associated with the use of radioisotopes to treat cancer. [1]
Answer: MODEL ANSWER GIVEN BELOW
 Allow 1 credit. Acceptable responses include, but are not limited to:
             Nuclear radiation is harmful to all living cells.
             Radioisotopes can cause gene mutations.
             Treatments can cause stomach problems, such as nausea.


83.
83 Compare the penetrating power of the two emissions from the Co-60. [1]
Answer: MODEL ANSWER GIVEN BELOW
 Allow 1 credit. Acceptable responses include, but are not limited to:
             Gamma radiation has greater penetrating power.
             Beta particles have weaker penetrating power.


84.
84 Complete the nuclear equation in your answer booklet for the beta decay of the Co-60
   by writing an isotopic notation for the missing product. [1]
Answer: MODEL ANSWER GIVEN BELOW
 Allow 1 credit. Acceptable responses include, but are not limited to:
             60Ni
             28
             60Ni
             nickel-60


85.
85 Determine the total time that will have elapsed when 12.5 grams of the original Co-60
   sample at the hospital remains unchanged. [1]
Answer: MODEL ANSWER GIVEN BELOW
 Allow 1 credit. Acceptable responses include, but are not limited to:
             15.813 y
             15.8 y



  Try the Quiz :     Physical Setting / Chemistry - New York Regents January 2012 Exam


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