National Science Olympiad 2013
Page 1 of 26
School Name _________________
Materials Science
May 18, 2013
National Science Olympiad
Team# _______________ SchoolName _________________________
StudentNames_____________________
__________________________
Instructions: This exam consists of 100 multiple choice questions and seven
Experimental Activities. Students may write on the exam. Multiple choice questions
are scored as the Number Correct – 0.2 Number Incorrect.
Place the answers to the multiple choice section on the provided answer sheet. The
exam may be separated, but be sure it is properly re-assembled. Answers not placed
on the answer sheet will not be scored.
Place answers to the Experimental Activities in the exam. Points are given by each
Experimental Activity
Total Score is determined by summation of acquired points.
Score=
M/C
Stress
Curve
Mod.
Crystal
Angle
Surf
Deter
=
Total
A penalty of up to 10% will be assessed if the lab station is not cleaned by the student participants by
the end of the event time. Ties are broken by quality and completeness of Stress-Strain Curve of
Parafilm. SignatureEventSupervisor:__________________ SignatureEventAssistant:______________________
Dr. Forrest S. Schultz
Department of Chemistry
University of Wisconsin-Stout
National Science Olympiad 2013
Page 2 of 26
School Name _________________
MultipleChoiceAnswersmustplacedonAnswerSheetprovidedatendofexam.
MultipleChoiceisscoredas:NumberCorrect–0.2NumberIncorrect.
1) A solid has a very high melting point, great hardness, and poor electrical conduction. This is a(n) __________ solid.
A) ionic
B) molecular
C) metallic
D) covalent network
E) metallic and covalent network
2) Which of the following is not a type of solid?
A) ionic
B) molecular
C) supercritical
D) metallic
E) covalent-network
3) Crystalline solids differ from amorphous solids in that crystalline solids have __________.
A) appreciable intermolecular attractive forces
B) a long-range repeating pattern of atoms, molecules, or ions
C) atoms, molecules, or ions that are close together
D) much larger atoms, molecules, or ions
E) no orderly structure
4) The unit cell with all sides the same length and all angles equal to 90° that has lattice points only at the corners is called
__________.
A) monoclinic
B) body-centered cubic
C) primitive cubic
D) face-centered cubic
E) spherical cubic
5) Which one of the following cannot form a solid with a lattice based on the sodium chloride structure?
A) NaBr
B) LiF
C) RbI
D) CuO
E) CuCl2
6) Consider the following statements about crystalline solids:
(i) Molecules or atoms in molecular solids are held together via
intermolecular forces.
(ii) Metallic solids have atoms in the points of the crystal lattice.
(iii) Ionic solids have formula units in the point of the crystal lattice.
(iv) Atoms in covalent-network solids are connected via a network
of covalent bonds.
Which of the statements is false?
A) (i)
B) (ii)
C) (iii)
D) (iv)
E) none
Dr. Forrest S. Schultz
Department of Chemistry
University of Wisconsin-Stout
National Science Olympiad 2013
Page 3 of 26
School Name _________________
7) The scattering of light waves upon passing through a narrow slit is called __________.
A) diffusion
B) grating
C) diffraction
D) adhesion
E) incidence
8) What fraction of the volume of each corner atom is actually within the volume of a face-centered cubic unit cell?
A) 1
B) 1/2
C) 1/4
D) 1/8
E) 1/16
9) What portion of the volume of each atom or ion on the face of a unit cell is actually within the unit cell?
A) 1/2
B) 1/4
C) 3/4
D) all of it
E) none of it
10) An alloy is a
A) heterogeneous mixture of two metals.
B) pure metal.
C) metallic material that is composed of two or more elements.
D) nonmetal with some properties of a metal.
E) a mineral containing two or more metals.
11) Steel is
A) an alloy of iron.
B) pure iron.
C) oxidized iron.
D) a mixture of iron and silver.
E) a liquid at room temperature.
12) Which one of the following is a property of most metals?
A) low melting point
B) brittleness
C) high electronegativity
D) thermal conductivity
E) acidic oxides
13) For a substitutional alloy to form, the two metals combined must have similar
A) ionization potential and electron affinity.
B) number of valance electrons and electronegativity.
C) reduction potential and size.
D) atomic radii and chemical bonding properties.
E) band gap and reactivity.
14) What is the typical effect of the addition of an interstitial element on the properties of a metal?
A) increase in malleability and corrosion resistance
B) increase in hardness and strength, decrease in ductility
C) decrease in melting point and increase in ductility
D) decrease in conductivity and increase in brittleness
E) increased surface luster
Dr. Forrest S. Schultz
Department of Chemistry
University of Wisconsin-Stout
National Science Olympiad 2013
Page 4 of 26
School Name _________________
15) Heterogeneous alloys
A) have properties that depend on composition.
B) have properties that depend on the manner in which the melt is solidified.
C) have properties that depend on the manner in which the solid is formed.
D) All of the above are true.
16) Intermetallic compounds are examples of
A) homogeneous alloys.
B) heterogeneous alloys.
C) interstitial alloys.
D) solution alloys.
E) ionic compounds.
17) Which of the following is not an alloy?
A) brass
B) steel
C) sterling silver
D) dental amalgam
E) ceramic
18) Alloys generally differ from compounds in that
A) the former always contain some carbon.
B) the former always contain some iron.
C) the former always have semiconductor properties.
D) the atomic ratios of the constituent elements in the former are not fixed and may vary over a wide range.
E) the former never contain a transition element.
19) Which element is typically not added to steel to modify its properties?
A) carbon
B) vanadium
C) chromium
D) nitrogen
E) nickel
20) Which property of metals cannot be explained with the electron-sea model?
A) shine
B) high thermal conductivity
C) high electric conductivity
D) malleability and ductility
E) trends in melting points
21) If the electronic structure of a solid substance consists of a valence band that is completely filled with electrons and there is a large
energy gap to the next set of orbitals, then this substance will be a(n) __________.
A) alloy
B) insulator
C) conductor
D) semiconductor
E) nonmetal
22) CsCl crystallizes in a unit cell that contains a Cs+ ion at the center of a cube and a Cl- ion at each corner. The unit cell of CsCl is
__________.
A) close packed
B) body-centered cubic
C) face-centered cubic
D) amorphous
E) primitive cubic
Dr. Forrest S. Schultz
Department of Chemistry
University of Wisconsin-Stout
National Science Olympiad 2013
Page 5 of 26
School Name _________________
23) NaCl crystallizes in a face-centered cubic cell. What is the total number of ions (Na+ ions and Cl- ions) that lie within a unit cell
of NaCl?
A) 2
B) 4
C) 8
D) 6
E) 5
24) An ionic solid, NaCl (s), dissolves in water because of the __________.
A) relatively low lattice energy due to small charges of Na+ and Cl- ions
B) simple face-centered cubic unit cell type it forms
C) 1:1 ratio of ions in the unit cell
D) strong coulombic interactions between oppositely charged ions
E) relatively low melting point
25) The process of doping can produce a __________ which can greatly __________ intrinsic conductivity.
A) n-type semiconductor, increase
B) p-type semiconductor, decrease
C) non-metal, increase
D) non-metal, decrease
E) allotrope, diminish
26) Of the following, only __________ is not a polymer.
A) cellulose
B) nylon
C) starch
D) protein
E) stainless steel
27) Which one of the following is an addition polymer with the same structure as polyethylene except that one hydrogen on every
other carbon is replaced by a benzene ring?
A) polyvinyl chloride
B) polypropylene
C) polystyrene
D) polyurethane
E) nylon 6, 6
28) Which of the following is not a natural polymer?
A) silk
B) starch
C) protein
D) cellulose
E) nylon
29) PVC is a polymer. What does PVC stands for?
A) Poly Viscous Chromium
B) Poly Viscose Ceramic
C) Poly Vinyl Chloride
D) Poly Vinyl Carbonate
30) Kevlar is used to make Formula 1 racing cars and bullet proof vests. What is Kevlar?
A) A type of wood
B) A type of plastic (polymer)
C) A type of metal
D) A composite of a polymer and a ceramic
E) a ceramic
Dr. Forrest S. Schultz
Department of Chemistry
University of Wisconsin-Stout
National Science Olympiad 2013
Page 6 of 26
School Name _________________
31) An elastomer will fail to regain its original dimensions following a distortion beyond its __________.
A) glass transition
B) phase boundary
C) London force
D) crystallinity
E) elastic limit
32) As a polymer becomes more crystalline, __________.
A) its melting point decreases
B) its density decreases
C) its stiffness decreases
D) its yield stress decreases
E) None of the above is correct.
33) The monomer that is polymerized to make natural rubber is __________.
A) melamine
B) formaldehyde
C) ethylene
D) isoprene
E) adipic acid
34) Natural rubber is too soft and chemically reactive for practical applications. Vulcanization of natural rubber entails __________.
A) conversion of an addition polymer to a condensation polymer
B) conversion of a condensation polymer to an addition polymer
C) increasing the average molecular weight of a condensation polymer
D) decreasing the average molecular weight of an addition polymer
E) crosslinking reactive polymer chains with sulfur atoms
35) Which of the following are the correct order in cost?
A) Steel<Silver<Gold<Platinum
B) Silver<Gold<Steel<Platinum
C) Platinum<Gold<Steel<Silver
D) Steel<Silver<Platinum<Gold
36) Which of the following is not classified as a nanomaterial?
A) isoprene
B) buckminsterfullerene
C) carbon nanotubes
D) graphene
E) All of the above are classified as nanomaterials
37) The properties of graphene include __________.
A) high strength
B) low thermal conductivity
C) a zero energy gap
D) a and c
E) a, b and c
38) Gallium crystallizes in a primitive cubic unit cell. The length of the unit cell edge is 3.70 Å.
The radius of a Ga atom is __________ Å.
A) 7.40
B) 3.70
C) 1.85
D) 0.930
E) Insufficient data is given.
Dr. Forrest S. Schultz
Department of Chemistry
University of Wisconsin-Stout
National Science Olympiad 2013
Page 7 of 26
School Name _________________
39) 18 karat gold contains __________% gold.
A) 18
B) 25
C) 89
D) 75
E) 1.0 x 102
40) The class of semiconductors, known as elemental, has special features. These are __________.
A) band gap and individual element valence electrons
B) periodical table grouping and diamond crystal structure
C) tetrahedral coordination geometry and sp2 hybrid orbitals
D) overlapping hybrid orbitals and filed conduction bands
E) none of the above
41) Blue LEDs are usually made of __________.
A) GaAs
B) GaP
C) GaO
D) GaS
E) GaN
42) A category __________ plastic container will generally be the most easily recycled.
A) 1
B) 2
C) 3
D) 4
E) 22
43) When the size of a semiconductor particle or crystal __________, the band gap energy __________.
A) decreases, decreases
B) decreases, remains the same
C) increases, increases
D) decreases, increases
E) decreases, goes to zero
44) Crystalline solids __________.
A) have their particles arranged randomly
B) have highly ordered structures
C) are usually very soft
D) exist only at high temperatures
E) exist only at very low temperatures
45) In liquids, the attractive intermolecular forces are __________.
A) very weak compared with kinetic energies of the molecules
B) strong enough to hold molecules relatively close together
C) strong enough to keep the molecules confined to vibrating about their fixed lattice points
D) not strong enough to keep molecules from moving past each other
E) strong enough to hold molecules relatively close together but not strong enough to keep molecules from moving past each other
46) As a solid element melts, the atoms become __________ and they have __________ attraction for one another.
A) more separated, more
B) more separated, less
C) closer together, more
D) closer together, less
E) larger, greater
Dr. Forrest S. Schultz
Department of Chemistry
University of Wisconsin-Stout
National Science Olympiad 2013
Page 8 of 26
School Name _________________
47) Which of the following is the hardest material on earth?
A) Diamond
B) Titanium
C) Kevlar
D) Gold
48) A gas is __________ and assumes __________ of its container whereas a liquid is __________ and assumes __________ of its
container.
A) compressible, the volume and shape, not compressible, the shape of a portion
B) compressible, the shape, not compressible, the volume and shape
C) compressible, the volume and shape, compressible, the volume
D) condensed, the volume and shape, condensed, the volume and shape
E) condensed, the shape, compressible, the volume and shape
49) Rhodium (atomic mass 102.9 g/mol) crystallizes in a face-centered cubic unit cell. In addition, rhodium has an atomic radius of
135 pm. What is the density (in g/cm3) of rhodium?
A) 1.53 g/cm3
B) 6.14 g/cm3
C) 17.4 g/cm3
D) 12.3 g/cm3
E) 27.8 g/cm3
50) Which statement is true about liquids but not true about solids?
A) They flow and are highly ordered.
B) They are highly ordered and not compressible.
C) They flow and are compressible.
D) They assume both the volume and the shape of their containers.
E) They flow and are not compressible.
51) The strongest interparticle attractions exist between particles of a __________ and the weakest interparticle attractions exist
between particles of a __________.
A) solid, liquid
B) solid, gas
C) liquid, gas
D) liquid, solid
E) gas, solid
52) Of the following substances, only __________ has London dispersion forces as its only intermolecular force.
A) H2O
B) CCl4
C) HF
D) CH3COOH
E) PH3
53) If rods of these materials are the same size, which would be the lightest?
A) Steel
B) Titanium
C) Aluminum
D) Gold
E) Glass
54) Which one of the following should have the lowest boiling point?
A) PH3
B) H2S
C) HCl
D) SiH4
E) H2O
Dr. Forrest S. Schultz
Department of Chemistry
University of Wisconsin-Stout
National Science Olympiad 2013
Page 9 of 26
School Name _________________
55) Of the following substances, __________ has the highest boiling point.
A) H2O
B) CO2
C) CH4
D) Kr
E) NH3
56) If you made a rod out of each of the following materials, which one would be the most flexible without permanently bending or
breaking?
A) Glass Fibre Reinforced Composites
B) Steel alloy
C) Aluminum alloy
D) Glass
57) In which of the following molecules is hydrogen bonding likely to be the most significant component of the total intermolecular
forces?
A) CH4
B) C5H11OH
C) C6H13NH2
D) CH3OH
E) CO2
58) __________ are particularly polarizable.
A) Small nonpolar molecules
B) Small polar molecules
C) Large nonpolar molecules
D) Large polar molecules
E) Large molecules, regardless of their polarity,
59) For a metals that crystallizes in face-centered cubic unit cell, what percentage of the space in the cell is occupied by the metal
atoms?
A) 47%
B) 52%
C) 68%
D) 74%
E) 87%
60) An oxide is a combination of metals atoms with oxygen atoms. Which oxide is commonly used in white paints?
A) Magnesium
B) Titanium
C) Zinc
D) Silver
E) Calcium
61) As well as jewelry, where else are diamonds commonly used
A) Satellites
B) Computers
C) Drill tips
D) Car engines
E) Baby diapers
Dr. Forrest S. Schultz
Department of Chemistry
University of Wisconsin-Stout
National Science Olympiad 2013
Page 10 of 26
School Name _________________
63) __________ is the energy required to expand the surface area of a liquid by a unit amount of area.
A) Viscosity
B) Surface tension
C) Volatility
D) Meniscus
E) Capillary action
64) Which statements about viscosity are true?
(i) Viscosity increases as temperature decreases.
(ii) Viscosity increases as molecular weight increases.
(iii) Viscosity increases as intermolecular forces increase.
A) (i) only
B) (ii) and (iii)
C) (i) and (iii)
D) none
E) all
65) The shape of a liquid's meniscus is determined by __________.
A) the viscosity of the liquid
B) the type of material the container is made of
C) the relative magnitudes of cohesive forces in the liquid and adhesive forces between the liquid and its container
D) the amount of hydrogen bonding in the liquid
E) the volume of the liquid
66) Viscosity is __________.
A) the "skin" on a liquid surface caused by intermolecular attraction
B) the resistance to flow
C) the same as density
D) inversely proportional to molar mass
E) unaffected by temperature
67) How high a liquid will rise up a narrow tube as a result of capillary action depends on __________.
A) the magnitudes of cohesive forces in the liquid and adhesive forces between the liquid and the tube, and gravity
B) gravity alone
C) only the magnitude of adhesive forces between the liquid and the tube
D) the viscosity of the liquid
E) only the magnitude of cohesive forces in the liquid
68) The property responsible for the "beading up" of water is __________.
A) density
B) viscosity
C) vapor pressure
D) surface tension
E) hydrogen bonding
69) Heat of sublimation can be approximated by adding together __________ and __________.
A) heat of fusion, heat of condensation
B) heat of fusion, heat of vaporization
C) heat of freezing (solidification), heat of condensation
D) heat of freezing (solidification), heat of vaporization
E) heat of deposition, heat of vaporization
Dr. Forrest S. Schultz
Department of Chemistry
University of Wisconsin-Stout
National Science Olympiad 2013
Page 11 of 26
School Name _________________
70) Which of the following statements is false?
A) The absolute value of the heat of sublimation is equal to the absolute value of the heat of deposition.
B) The heat of sublimation is equal to the sum of the heat of vaporization and the heat of melting.
C) The heat of sublimation is equal to the sum of the heat of vaporization and the heat of freezing.
D) The absolute value of the heat of sublimation is equal to the absolute value of the sum of the heat of condensation and the heat of
freezing.
E) The absolute value of the heat of deposition is equal to sum of the absolute value of the heat of vaporization and the absolute value
of the heat of freezing.
71) Which precious stone, often used in jewelry, is also often used in laser technology?
A) Diamond
B) Ruby
C) Emerald
D) Sapphire
72) Based on the following information, which compound has the strongest intermolecular forces?
Substance
Argon (Ar)
Benzene (C6H6)
Ethanol (C2H5OH)
Water (H2O)
Methane (CH4)
ΔHvap(kJ/mol)
6.3
31.0
39.3
40.8
9.2
A) Argon
B) Benzene
C) Ethanol
D) Water
E) Methane
73) A substance that expands to fill its container yet has a density approaching that of a liquid, and that can behave as a solvent is
called a(n) __________.
A) plasma
B) gas
C) liquid
D) amorphous solid
E) supercritical fluid and gas
74) As a space shuttle re-enters the atmosphere the temperature of the outer material increases dramatically. What is this temperature
that is typically achieved?
A) 0 – 500 °C
B) 500 – 1000 °C
C) 1000 – 1500 °C
D) >2000 °C
75) Of the following, __________ is an exothermic process.
A) melting
B) subliming
C) freezing
D) boiling
E) All of the above are exothermic.
Dr. Forrest S. Schultz
Department of Chemistry
University of Wisconsin-Stout
National Science Olympiad 2013
Page 12 of 26
School Name _________________
76) A volatile liquid is one that __________.
A) is highly flammable
B) is highly viscous
C) is highly hydrogen-bonded
D) is highly cohesive
E) readily evaporates
77) In general, the vapor pressure of a substance increases as __________ increases.
A) surface tension
B) molecular weight
C) hydrogen bonding
D) viscosity
E) temperature
78) Which of the following is most likely to exhibit liquid-crystalline behavior?
A) CH3CH2-C(CH3)2-CH2CH3
B) CH3CH2CH2CH2CH2CH2CH2CH3
C) CH3CH2CH2CH2CH2-Na+
D)
E)
79) In the smectic A liquid-crystalline phase, __________.
A) the molecules are aligned along their long axes, with no ordering with respect to the ends of the molecules
B) the molecules are arranged in sheets, with their long axes parallel and their ends aligned as well
C) the molecules are aligned with their long axes tilted with respect to a line perpendicular to the plane in which the molecules are
stacked
D) disk-shaped molecules are aligned through a stacking of the disks in layers
E) the molecules are oriented in a totally random fashion
80) In the __________ liquid crystalline phase, the component molecules exhibit only one dimensional ordering.
A) nematic
B) smectic A
C) smectic B
D) smectic C
E) cholesteric
81) In the ________ liquid crystalline phase, the component molecules are aligned along their long axis and are arranged in layers
with the molecules in each plane twisted slightly in relation to the molecules in the planes above and below.
A) nematic
B) smectic A
C) smectic B
D) smectic C
E) cholesteric
Dr. Forrest S. Schultz
Department of Chemistry
University of Wisconsin-Stout
National Science Olympiad 2013
Page 13 of 26
School Name _________________
82) Based on molecular mass and dipole moment of the five compounds in the table below, which should have the highest boiling
point?
A) CH3CH2CH3
B) CH3OCH3
C) CH3Cl
D) CH3CHO
E) CH3CN
83) The heat curve generated above pertains to question 83-86 The slope of the __________ segment corresponds to the heat capacity
of the liquid of the substance.
A) AB
B) BC
C) CD
D) DE
E) EF
84) The heating curve shown was generated by measuring the heat flow and temperature for a solid as it was heated. The slope of the
__________ segment corresponds to the heat capacity of the solid.
A) AB
B) BC
C) CD
D) DE
E) EF
Dr. Forrest S. Schultz
Department of Chemistry
University of Wisconsin-Stout
National Science Olympiad 2013
Page 14 of 26
School Name _________________
85) The heating curve shown was generated by measuring the heat flow and temperature for a solid as it was heated. The slope of the
__________ segment corresponds to the heat capacity of the gas.
A) AB
B) BC
C) CD
D) DE
E) EF
86) The heating curve shown was generated by measuring the heat flow and temperature of a solid as it was heated. The heat flow into
the sample in the segment __________ will yield the value of the ΔHvap of this substance.
A) AB
B) BC
C) CD
D) DE
E) EF
87) On the phase diagram shown above, segment __________ corresponds to the conditions of temperature and pressure under which
the solid and the gas of the substance are in equilibrium.
A) AB
B) AC
C) AD
D) CD
E) BC
88) On the phase diagram shown above, the coordinates of point __________ correspond to the critical temperature and pressure.
A) A
B) B
C) C
D) D
E) E
89) The enthalpy change for converting 1.00 mol of ice at -50.0°C to water at 70.0°C is __________ kJ. The specific heats of ice,
water, and steam are 2.09 J/g-K, 4.18 J/g-K, and 1.84 J/g-K, respectively. For H2O, ΔHfus = 6.01 kJ/mol, and ΔHvap = 40.67 kJ/mol
A) 12.28
B) 6.41
C) 13.16
D) 7154
E) 9.40
Dr. Forrest S. Schultz
Department of Chemistry
University of Wisconsin-Stout
National Science Olympiad 2013
Page 15 of 26
School Name _________________
90) Which imaging technique is commonly used in Materials Science?
A) SEM
B) TEM
C) AFM
D) STM
E) All of the above
91) Rank the following from low to high for expected Young’s Modulus values:
A) HDPE >Al >Oak Wood >SiC >Steel
B) SiC >Al >Oak Wood > HDPE >Steel
C) SiC > Steel > Al >Oak Wood > HDPE
D) SiC > Steel > Al > HDPE > Oak Wood
E) SiC > Al > Steel > HDPE > Oak Wood
Above is a stress–strain curve of a structural steel, place the appropriate numbers/letters by the descriptions below:
92) ____ Ultimate Strength
93) ____ Yield Strength
94) ____ Rupture
95) ____ Strain hardening region
96) ____ Necking region.
97) ____ Apparent stress (F/A0)
98) ____ Actual stress (F/A)
99) Young’s Modulus is a measure of a material’s _____________.
A) density
B) volume
C) elasticity
D) hardness
E) conductivity
Dr. Forrest S. Schultz
Department of Chemistry
University of Wisconsin-Stout
National Science Olympiad 2013
Page 16 of 26
School Name _________________
100) For an application in which there is a large pulling force (tension), what type of Young’ Modulus for a material would
be preferred?
A) low Young’s Modulus
B) high Young’s Modulus
C) either A or C
D) medium Young’s Modulus
E) cannot determine
Dr. Forrest S. Schultz
Department of Chemistry
University of Wisconsin-Stout
National Science Olympiad 2013
Page 17 of 26
School Name _________________
MaterialsPerformanceandCharacterizationLabSection
Answerstobeplacedbelow.AllanswersaretobeinSIunits.
(10points)1.Forthematerialsprovided,drawtheexpectedQUALITATIVEstress-straincurvesonewouldexpectonthe
axisbelowforaTensileStrengthexperiment.Drawallofthecurvesonthesameaxis.Labeleachcurvewiththe
correspondingmaterial.
Providedmaterials:blackplastic,rubberband,parafilm,paperandpapertowel.
Stress
Dr. Forrest S. Schultz
Strain
Department of Chemistry
University of Wisconsin-Stout
National Science Olympiad 2013
Page 18 of 26
School Name _________________
(20 points) 2. A Tensile Strength experiment is to be performed with Parafilm. Students are to collect data and
develop a stress-strain curve on the grid below. In addition to axis labels, these points are to be clearly labeled
on the graph: Tensile Strength/Stress (fracture), Yield Strength, Region of Elasticity, Strain
Hardening/Strengthening Region.
Experimental Notes: This experiment must be conducted carefully! The addition of coins must be one at a time
with a rate of about one coin per second. Be sure to follow the setup instructions provided by the Event
Supervisor.
Dr. Forrest S. Schultz
Department of Chemistry
University of Wisconsin-Stout
National Science Olympiad 2013
Page 19 of 26
School Name _________________
(10points)3.BasedonyourTensileStrengthExperimentofParafilm,answerthefollowingquestions.Showallwork
whereappropriate.
a.DeterminetheYoung’sModulusofParafilm.IndicateontheStress-Straincurvewhichdatayouareusing.
b.DeterminethePoisson’sratioofParafilm.Drawanexamplediagramofthemeasurementsyouaremaking.
c.DeterminetheTensileStrengthinMPa
d.OncetheParafilmbreaks,isthereanyelasticityremaininginthefilm?Explainyouranswerandjustifywithdata.
Dr. Forrest S. Schultz
Department of Chemistry
University of Wisconsin-Stout
National Science Olympiad 2013
Page 20 of 26
School Name _________________
(10points)4.Constructacrystalstructure.Usingtheprovidedtoothpicksandmarshmallows,assembleTWOconnected
unitcellsofChromiumwhichhasaBCCunitcell.Onthestructureuseadifferentcolorofmarshmallowstoindicateallof
theatomsthatfallonthe(102)plane.Thisstructureistobehanded-intotheEventSupervisorforgrading.Youmay
usethespacebelowforscratchpaper.
Dr. Forrest S. Schultz
Department of Chemistry
University of Wisconsin-Stout
National Science Olympiad 2013
Page 21 of 26
School Name _________________
IntermolecularForcesandSurfaceChemistryLabSection
Answerstobeplacedbelow
(18points)5.DeterminetheContactAngleforthreeLiquidsonthesurfacesofthecoatingsontheTHREEprovided
microscopeslides(SlideAandSlideBandSlideC).Thesecoatingsarefragile,sodonotattempttocleantheslides.
Placeoneliquidontheslideatatimetomakeyourmeasurements.Drawtheimageofthedropyouareobservingon
thediagramsbelow.Drawintheappropriatecontactangleandlabeltheangleonthecorrectdiagramsbelow.
LiquidX
SlideA
SlideB
SlideC
SlideA
SlideB
SlideC
SlideA
SlideB
SlideC
LiquidY
LiquidZ
Dr. Forrest S. Schultz
Department of Chemistry
University of Wisconsin-Stout
National Science Olympiad 2013
Page 22 of 26
School Name _________________
(20points)6.Capillaryactionisaphenomenonwhereliquidisdrawnupatubeorductwithouttheuseofexternal
force.Inthisactivity,youwilluseglasscapillarytubestoinvestigatethispropertyandrelateittointermolecularforces.
Capillaryactionandsurfacetensionarerelatedbytheequation:
!
*
"
+
Surfacetension(β)= ∗ $%&(ℎ + )
Whereρisthedensityofthefluid,gisthegravitationalconstant(9.8m/s2),histheheightofthecapillaryrise(inm)and
ristheradiusofthecapillarytube.
CAUTION:Glasscapillarytubesarefragileandverysharpifbroken!Handlethemwithcare!
a. AsmallbeakerwithLiquidXhasbeenprovided.Insertadrycapillarytubeintothisbeakerandmeasurethe
capillaryrise(h)withacaliper.Recordthismeasurementbelowinmeters.
b. RepeatusinganewcapillarytubeandLiquidY.
c. RepeatusinganewcapillarytubeandLiquidZ.
d. Answerthequestionsbelow
LiquidXh:____________
LiquidYh:____________
LiquidZh:____________
Calculatethesurfacetensionforthethreeliquidsandplacetheanswersintheboxesbelow.ThedensityofLiquidsXand
Yis1,000kg/m3.ThedensityofLiquidZis800kg/m3.AnswersaretobeinSIUnits.
SurfaceTensionLiquidX
Dr. Forrest S. Schultz
SurfaceTensionLiquidY
SurfaceTensionLiquidZ
Department of Chemistry
University of Wisconsin-Stout
National Science Olympiad 2013
Page 23 of 26
School Name _________________
(12points)7.a.Detergentsaremoleculesthatarebothhydrophilicandhydrophobicandaretermedamphiphilic
molecules.Inthespacebelowdrawthespecificinteractions(showspecificatomicandmolecularforces)andgeometry
ofthreeanionicdetergentmoleculessuchasSDS(sodiumdodecylsulfate)onthesurfaceofwater.
b.Explainwiththeuseofintermolecularforcediagrams/drawings,whytheSDSmoleculeformsamono-layeronthe
surfaceofwaterand“doesnotmix”intothewater.Hint:Theanswerisnot“becauseSDShasahydrophobictail.”
Dr. Forrest S. Schultz
Department of Chemistry
University of Wisconsin-Stout
National Science Olympiad 2013
Page 24 of 26
School Name _________________
7.Continued
c.OncetheconcentrationofSDSreachesasignificantconcentration,andsomeairisintroducedintothesystem,
bubblescanform!Drawastructureofacross-sectionofabubblefilm.Labelthefollowingitems:SDS,water,andair.
Onthisdrawingestimatethethicknessofthefilminnm(nanometers).
Dr. Forrest S. Schultz
Department of Chemistry
University of Wisconsin-Stout
National Science Olympiad 2013
Page 25 of 26
School Name _________________
Team#_______TeamName________________________StudentNames__________________________________
MultipleChoiceAnswerSheet
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Dr. Forrest S. Schultz
Department of Chemistry
University of Wisconsin-Stout
National Science Olympiad 2013
Page 26 of 26
School Name _________________
Properuseofcaliper:ThecaliperinFigure1showsameasureddiameterof3.13cm.3.1cmwasreadfromthefixedscale,
usingthefirst(0)lineonthemoveablescaleastheindex.The3wasreadfromthemoveablescale.Itisthelinethatisexactly
inlinewithanotherlineinthefixedscale.
Dr. Forrest S. Schultz
Department of Chemistry
University of Wisconsin-Stout