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Contests
National and Regional Contests
USA Contests
USA Physics and Chemistry Contests
National Chemistry Olympiad
2004 National Chemistry Olympiad
2004 National Chemistry Olympiad
Part of
National Chemistry Olympiad
Subcontests
(11)
50
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2004 USNCO Problem 50: Valence Electrons
How many valence electrons are in the pyrophosphate ion, \ce{P2O7}^{4-}?
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<span class='latex-bold'>(A) </span> 48\qquad<span class='latex-bold'>(B) </span> 52\qquad<span class='latex-bold'>(C) </span> 54\qquad<span class='latex-bold'>(D) </span> 56\qquad
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48
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52
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54
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51
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2004 USNCO Problem 51: Bond Angle
Which species has the largest
F-A-F
\text{F-A-F}
F-A-F
bond angle where
A
\text{A}
A
is the central atom?
(A)
\ce{BF3} \qquad
(B)
\ce{CF4} \qquad
(C)
\ce{NF3}\qquad
(D)
\ce{OF2}\qquad
52
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2004 USNCO Problem 52: Carbon Monoxide Bond
The triple bond in carbon monoxide consists of
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3 sigma bonds
<span class='latex-bold'>(A) </span> \text{3 sigma bonds}\qquad
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3 sigma bonds
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2 sigma bonds and 1 pi bond
<span class='latex-bold'>(B) </span> \text{2 sigma bonds and 1 pi bond}\qquad
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2 sigma bonds and 1 pi bond
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1 sigma bond and 2 pi bonds
<span class='latex-bold'>(C) </span> \text{1 sigma bond and 2 pi bonds}\qquad
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1 sigma bond and 2 pi bonds
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3 pi bonds
<span class='latex-bold'>(D) </span> \text{3 pi bonds}\qquad
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53
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2004 USNCO Problem 53: Boiling Points
The boiling points of the halogens, \ce{F2}, \ce{Cl2}, \ce{Br2} and \ce{I2} increase in that order. This is best attributed to differences in
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covalent bond strengths
<span class='latex-bold'>(A) </span>\text{covalent bond strengths}\qquad
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covalent bond strengths
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dipole forces
<span class='latex-bold'>(B) </span>\text{dipole forces}\qquad
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dipole forces
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London dispersion forces
<span class='latex-bold'>(C) </span>\text{London dispersion forces}\qquad
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London dispersion forces
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colligative forces
<span class='latex-bold'>(D) </span>\text{colligative forces}\qquad
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colligative forces
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2004 USNCO Problem 54: Polar
Which species is polar?
(A)
\ce{CO2} \qquad
(B)
\ce{SO2}\qquad
(C)
\ce{SO3}\qquad
(D)
\ce{O2}\qquad
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2004 USNCO Problem 55: n-butane
Which formula represents n-butane?
(A)
\ce{CH3CH2CH2CH3} \qquad
(B)
\ce{CH2=CHCH2CH3} \qquad
(C)
\ce{(CH3)2CHCH3} \qquad
(D)
\ce{(CH3)3CH}\qquad
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2004 USNCO Problem 56: Isomers
How many structural isomers have the formula \ce{C3H6Cl2}?
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<span class='latex-bold'>(A) </span>1\qquad<span class='latex-bold'>(B) </span>2\qquad<span class='latex-bold'>(C) </span>3\qquad<span class='latex-bold'>(D) </span>4
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57
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2004 USNCO Problem 57: Hybridization
What is the hybridization of the carbon atom in a carboxyl group?
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<span class='latex-bold'>(A) </span>sp \qquad<span class='latex-bold'>(B) </span> sp^2\qquad<span class='latex-bold'>(C) </span> sp^3\qquad<span class='latex-bold'>(D) </span> dsp^3\qquad
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2004 USNCO Problem 58: Reaction with Alcohol
A reaction in which a carboxylic acid reacts with an alcohol to form an organic compound and water is called
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esterification
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hydrolysis
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neutralization
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saponification
<span class='latex-bold'>(A) </span> \text{esterification} \qquad<span class='latex-bold'>(B) </span> \text{hydrolysis}\qquad<span class='latex-bold'>(C) </span> \text{neutralization} \qquad<span class='latex-bold'>(D) </span> \text{saponification}\qquad
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esterification
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neutralization
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2004 USNCO Problem 59: Polymerization
What substance is formed when \ce{CF2=CF2} is polymerized?
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Polyethylene
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Teflon
<span class='latex-bold'>(A) </span> \text{Polyethylene} \qquad<span class='latex-bold'>(B) </span> \text{Polyurethane}\qquad<span class='latex-bold'>(C) </span> \text{PVC}\qquad<span class='latex-bold'>(D) </span> \text{Teflon}\qquad
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2004 USNCO Problem 60: Enzymes
Most enzymes are a type of
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Nucleic Acid
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Protein
<span class='latex-bold'>(A) </span> \text{Carbohydrate} \qquad<span class='latex-bold'>(B) </span> \text{Lipid} \qquad<span class='latex-bold'>(C) </span> \text{Nucleic Acid} \qquad<span class='latex-bold'>(D) </span> \text{Protein} \qquad
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