HS Sample Set 5, Round 14 from NSB
To identify the chemical compounds dissolved in a sample, a student dips a clean piece of nichrome wire into the sample and burns it in a flame. The flame burns red. What metal does the mixture probably contain?
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What are the decay mode and the daughter nuclide, respectively, of potassium-37?
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What is the maximum number of spheres with a radius of 1 that can fit inside a cube with edge lengths of 6?
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Find all points of inflection and extrema, including type, of the function $$f(x) = e^x + e^{\frac{x}{2}}\,. $$
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What is the phrase that describes the process of producing an electron and a positron when a high-energy photon travels through matter, directly converting radiant energy into matter?
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A living room has floor dimensions of 3.5 meters by 4.2 meters and a height of 2.4 meters. Given air density of 1.2 kg/m³ and g = 10 m/s², to the nearest ten, what does the air in the room weigh in newtons?
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Which of the following are NOT found in the thylakoid membranes of the chloroplast? W) Carotenoids X) Rubisco Y) Water Z) ADP
W: W) Carotenoids
X: X) Rubisco
Y: Y) Water
Z: Z) ADP
Answer: X) X) Rubisco
By name or number, order the following five cell layers in a eudicot root from most lateral to most medial: 1) pericycle; 2) epidermis; 3) endodermis; 4) phloem; 5) cortex.
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Give the specific name for the following functional group: a nitrogen atom bonded to two carbon chains and a hydrogen atom.
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At 25 °C the vapor pressure of water is about 3 kPa and the vapor pressure of methanol is about 15 kPa. Assuming no deviation from Raoult’s law, determine the vapor pressure, in kilopascals, of a mixture of 1 mol of methanol and 2 mol of water.
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The period of revolution of a particle traveling in uniform circular motion is a function of what two variables?
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You are asked to determine whether a king’s crown is really made of gold. You weigh the crown; it weighs 8 N in air and 7 N in water. Its volume is 0.0001 m³. Given that the density of gold is 19 000 kg/m³, lead is 11 000 kg/m³, and iron is 8 000 kg/m³, the king’s crown is made of which material?
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The freshwater and saltwater zones within coastal aquifers are separated by a transition zone, also called the zone of dispersion, within which there is mixing between freshwater and saltwater. Which state of the Northern Atlantic Coastal Plain Aquifer System has the shallowest depth to the top of the transition zone?
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In a stratified period of a lake, oxygen supplied directly by the atmosphere and photosynthetic organisms replenishes the dissolved oxygen of which of the following three
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Neglecting friction, a 33-kg cart rolls down a slope that is 20 m high and 60 m long. Using g = 10 m/s², what is the velocity in meters per second at the base of the slope?
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A long straight wire carries a 10 A current north. Give the magnitude in teslas and the direction of the magnetic field induced at a point 10 cm directly under the wire.
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Approximately how much energy does the Sun generate in joules per hour if it converts about 4 billion kilograms of mass into pure energy every second? W) 10⁹ X) 10¹⁸ Y) 10³⁰ Z) 10³³
W: W) 10⁹
X: X) 10¹⁸
Y: Y) 10³⁰
Z: Z) 10³³
Answer: Y) Y) 10³⁰
In the presence of alcohol dehydrogenase, the rate of reduction of acetaldehyde to ethanol increases as you increase the concentration of acetaldehyde. Eventually, the rate of reaction reaches a maximum, where further increases in the concentration of acetaldehyde have no effect. Which of the following BEST explains this result? W) All of the alcohol dehydrogenase molecules are bound to acetaldehyde molecules X) At high concentrations of acetaldehyde, the activation energy of the reaction decreases Y) The enzyme is no longer specific for acetaldehyde Z) At high concentrations of acetaldehyde, the change in free energy of the reaction decreases
W: W) All of the alcohol dehydrogenase molecules are bound to acetaldehyde molecules
X: X) At high concentrations of acetaldehyde, the activation energy of the reaction decreases
Y: Y) The enzyme is no longer specific for acetaldehyde
Z: Z) At high concentrations of acetaldehyde, the change in free energy of the reaction decreases
Answer: W) W) All of the alcohol dehydrogenase molecules are bound to acetaldehyde molecules
Populations P1 and P2 are normally distributed and have identical means; however, the standard deviation of P1 is twice the standard deviation of P2. Which of the following is TRUE about the percentage of observations falling within two standard deviations of the mean for each population? W) The percentage for P1 is twice the percentage for P2 X) The percentage for P1 is greater, but not twice as great, as the percentage for P2 Y) The percentage for P2 is twice the percentage for P1 Z) The percentages are identical
W: W) The percentage for P1 is twice the percentage for P2
X: X) The percentage for P1 is greater, but not twice as great, as the percentage for P2
Y: Y) The percentage for P2 is twice the percentage for P1
Z: Z) The percentages are identical
Answer: Z) Z) The percentages are identical
Find the second derivative of the function $$f(x) = (3 + 2x)e^{-3x}\,. $$
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Which of the following compounds is NOT a common cement in sedimentary rocks? W) SiO₂ X) Fe₂O₃ Y) Mg₂SiO₃ Z) CaCO₃
W: W) SiO₂
X: X) Fe₂O₃
Y: Y) Mg₂SiO₃
Z: Z) CaCO₃
Answer: Y) Y) Mg₂SiO₃
The Ghyben–Herzberg relation characterizes the relationship between the depth of freshwater occurring above and below sea level in the presence of a saltwater intrusion. What physical property determines this relationship?
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If the Coulomb constant is $9\times10^9\,$N·m²/C², what force, in newtons, will two particles with charges of +2 C and –2 C kept 2 m apart exert on each other? W) $4.5\times10^9$ away from each other X) $4.5\times10^9$ toward each other Y) $9.0\times10^9$ toward each other Z) $1.8\times10^{10}$ toward each other
W: W) $4.5\times10^9$ away from each other
X: X) $4.5\times10^9$ toward each other
Y: Y) $9.0\times10^9$ toward each other
Z: Z) $1.8\times10^{10}$ toward each other
Answer: Y) Y) $9.0\times10^9$ toward each other
Pam buys a pendulum clock at a discount store and discovers when she gets home that it loses 6 minutes each day. If the pendulum has a period of 2 seconds, by how much must the length be changed, to the nearest centimeter, so that the clock keeps accurate time?
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Which of the following statements is TRUE about Population I stars and II stars? W) Population I stars tend to be older than Population II stars X) Population I stars of a given mass tend to be more luminous than Population II stars of the same mass Y) Population I stars tend to be found in the spiral arms of galaxies, while Population II stars tend to be found in globular clusters Z) Population I stars tend to have fewer heavy elements than Population II stars
W: W) Population I stars tend to be older than Population II stars
X: X) Population I stars of a given mass tend to be more luminous than Population II stars of the same mass
Y: Y) Population I stars tend to be found in the spiral arms of galaxies, while Population II stars tend to be found in globular clusters
Z: Z) Population I stars tend to have fewer heavy elements than Population II stars
Answer: Y) Y) Population I stars tend to be found in the spiral arms of galaxies, while Population II stars tend to be found in globular clusters
Eclipsing binaries are binary star systems whose members eclipse each other, blocking one another’s light and thereby causing the system to look fainter to observers on Earth. Assuming that the eclipsing binary stars are spherical with circular orbits, by number, identify all of the following which could influence the light curve: 1) Orbital inclination; 2) Luminosities of the stars; 3) Orbital period; 4) Radii of the stars; 5) Spectral type of the stars.
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What is the term for a kind of landfill technology, currently in research and development, that accelerates the biological decomposition of organic wastes in a landfill by promoting the conditions necessary for the microorganisms that degrade the waste?
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When water levels drop in a spent nuclear fuel pool, temperatures in the fuel assembly rise, accelerating the oxidation of the material that encases uranium oxide pellets. If the oxidation reactions become self-sustaining, a fire can form that proceeds as a burn front along the axis of the fuel rod toward the source of the oxidant. What is the name of the encasing material that is burning?
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Cowbirds, common cuckoos, and African honeyguides lay their eggs in the nests of other birds. As a result, what term is typically used to describe these birds?
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By name or number, identify all of the following five choices that are NOT essential amino acids for humans: 1) Phenylalanine; 2) Alanine; 3) Tryptophan; 4) Histidine; 5) Aspartate.
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If $$x^2 + y^2 = 52\,, $$ find $$\frac{dy}{dx}$$ in terms of x and y in simplest form.
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A rectangle has both a changing height and a changing width, but the height and width change so that the area of the rectangle is always 200 ft². What is the rate of change of the width of the rectangle in feet per second when the height is 5 ft, if the height is decreasing at that moment at the rate of 0.5 ft/s?
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Which of the following organelles would you expect to be MOST active during apoptosis of the cells that contain them? W) Endoplasmic reticulum X) Golgi bodies Y) Lysosomes Z) Ribosomes
W: W) Endoplasmic reticulum
X: X) Golgi bodies
Y: Y) Lysosomes
Z: Z) Ribosomes
Answer: Y) Y) Lysosomes
What is the scientific name for a type of skin growth that looks different than a common mole? It is usually larger, with borders that are not easy to see, uneven colors, and is partially raised above the skin surface.
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Roughly, which of the following BEST represents the solar energy intensity in watts per square meter incident on the Earth? W) 200 X) 1,400 Y) 3,000 Z) 10,000
W: W) 200
X: X) 1,400
Y: Y) 3,000
Z: Z) 10,000
Answer: X) X) 1,400
Companies A, B, and C are forced to pay one dollar of tax per ton of carbon dioxide equivalent emissions. If Company A emits 100 tons of CO₂ and 4 tons of N₂O, Company B emits 10 tons of CO₂ and 5 tons of N₂O, and Company C emits 200 tons of CO₂ and no N₂O, which company has to pay the largest tax?
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By number, identify all of the following four situations in which an object is NOT in equilibrium: 1) moving to the right with constant velocity; 2) slowing to a stop; 3) moving with constant speed in a circle; 4) free fall.
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A brass ball with a mass of 200 g at 20 °C is placed in boiling water until it reaches equilibrium. Given that the specific heat of brass is 0.094 kcal/(kg·°C), how much thermal energy in kilocalories is absorbed by the ball?
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What is the name of a highly contagious, infectious viral disease in cows that causes symptoms such as respiratory disease, conjunctivitis, encephalitis, and brain infections?
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By name or number, identify all of the following five choices that are NOT arthropods: 1) Trilobites; 2) Chelicerates; 3) Crustaceans; 4) Icterids; 5) Polyplacophores.
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Which of the following series converges? W) $\sum_{n=1}^\infty \frac{1}{n^{0.5}}$ X) $\sum_{n=1}^\infty \frac{1}{n+1}$ Y) $\sum_{n=1}^\infty \frac{n}{e^n}$ Z) $\sum_{n=1}^\infty \frac{e^n}{n}$
W: W) $\sum_{n=1}^\infty \frac{1}{n^{0.5}}$
X: X) $\sum_{n=1}^\infty \frac{1}{n+1}$
Y: Y) $\sum_{n=1}^\infty \frac{n}{e^n}$
Z: Z) $\sum_{n=1}^\infty \frac{e^n}{n}$
Answer: Y) Y) $\sum_{n=1}^\infty \frac{n}{e^n}$
What is the limit of $$x^x$$ as $$x\to0^+$$?
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By name or number, identify all of the following four substances that are substitutional alloys: 1) Brass; 2) Steel; 3) Sterling silver; 4) Pewter.
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A chemist is trying to identify a chemical by determining its molar mass. A sample weighing 0.75 g was dissolved in 0.10 kg of benzene and the freezing point depression was determined to be 0.50 °C. Given the $K_f$ for benzene is 5 °C·kg/mol, what is the molar mass of the chemical in grams per mole to the nearest whole number?
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Which of the following is the closest to the maximum solar altitude for Barrow, Alaska in the course of a year? W) 90° X) 45° Y) 20° Z) 0°
W: W) 90°
X: X) 45°
Y: Y) 20°
Z: Z) 0°
Answer: X) X) 45°
By name or number, identify all of the following three properties that Zeeman splitting can be used to determine: 1) Presence of a magnetic field; 2) Strength of a magnetic field; 3) Metal abundances.
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A well near the beach is suspected to be contaminated with chloride ions from sea water. If chloride is present, which of the following will produce a cloudy suspension when mixed with the water? W) Silver nitrate X) Sodium nitrate Y) Potassium acetate Z) Calcium bromide
W: W) Silver nitrate
X: X) Sodium nitrate
Y: Y) Potassium acetate
Z: Z) Calcium bromide
Answer: W) W) Silver nitrate
The molar mass of carbon dioxide is 44 g/mol. Providing your answer to the nearest integer, if 88 g of solid carbon dioxide sublimates, how many liters of carbon dioxide gas will be formed at standard temperature and pressure?
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Amebocytes from Limulus organisms are currently used in the medical field to test for the presence of what substances?
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By name or number, identify all of the following five molecules that function as vertebrate neurotransmitters: 1) Endorphins; 2) Serotonin; 3) Biotin; 4) Enkephalins; 5) Dopamine.
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