Washington Comprehensive Assessment of Science — Grade 11

How does increasing the concentration of hydrochloric acid affect its reaction rate with zinc metal chips?

• AIt increases the reaction rate by increasing the frequency of collisions between reactant…
• BIt decreases the reaction rate by lowering the temperature of the acid solution.
• CIt stops the reaction by destroying all zinc atoms immediately.
• DIt has zero effect on the reaction rate.

Consider the reversible exothermic synthesis of ammonia: N2(g) + 3 H2(g) <=> 2 NH3(g) + Heat. If the temperature of the equilibrium system is increased, how will the reaction respond according to Le Chatelier's principle?

• AThe equilibrium will shift to the left (toward reactants N2 and H2) to absorb added therm…
• BThe equilibrium will shift to the right (toward product NH3) to generate more heat.
• CThe equilibrium position will remain completely unaffected.
• DThe reaction will produce solid nitrogen crystals.

A 1,200-kg car traveling east at 15 m/s collides head-on with an identical 1,200-kg car traveling west at 15 m/s. The cars lock bumpers and come to a complete stop. What was the total vector momentum of the system right before the collision?

• A0 kg·m/s.
• B36,000 kg·m/s east.
• C18,000 kg·m/s west.
• D72,000 kg·m/s north.

During protein synthesis, a cell transcribes a DNA sequence 3'-TAC GGC TTA-5' into messenger RNA. What is the complementary sequence of the mRNA transcript produced?

• A5'-AUG CCG AAU-3'.
• B5'-ATG CCG AAT-3'.
• C5'-UAC GGC UUA-3'.
• D5'-GCA TTA CCG-3'.

How do biological enzymes increase the rate of metabolic reactions inside living cells?

• ABy lowering the activation energy barrier required for the reaction to occur.
• BBy raising the total thermal energy of the cell by 50°C.
• CBy permanently changing the chemical identity of final product atoms.
• DBy consuming ATP energy to destroy water molecules.

In a population of wildflowers in Hardy-Weinberg equilibrium, the frequency of the recessive white-flower allele (q) is 0.3. What percentage of the population is expected to be heterozygous (2pq) for flower color?

• A42%.
• B9%.
• C49%.
• D70%.

Where are stable stars that fuse hydrogen into helium in their cores (such as our Sun) located on a Hertzsprung-Russell (H-R) diagram?

• AAlong the diagonal Main Sequence band.
• BIn the White Dwarf lower-left region.
• CIn the Red Supergiant top-right corner.
• DIn the Black Hole center singularity.

According to Kepler's Third Law of Planetary Motion, how does the orbital period of a planet change as its average distance (radius) from the Sun increases?

• AThe orbital period increases because T² is proportional to r³.
• BThe orbital period decreases because gravity pulls faster at greater distances.
• CThe orbital period remains constant regardless of distance.
• DThe orbital period drops to zero.

Which flux in the global carbon cycle removes carbon dioxide gas directly from the atmosphere and stores it in the biosphere?

• APhotosynthesis by terrestrial forests and oceanic phytoplankton.
• BCombustion of coal and crude oil.
• CVolcanic degassing of magma.
• DCellular respiration by animals.

A team of environmental engineers designs a battery energy storage facility for a Washington wind farm. Lithium-ion batteries offer high energy density (criterion) but present thermal runaway fire risks (constraint). Flow batteries have lower energy density but zero fire risk. How should engineers evaluate the options?

• APerform a multi-criteria trade-off matrix balancing energy density, safety risk, lifecycl…
• BSelect lithium-ion batteries and disable all thermal safety monitoring.
• CSelect flow batteries and claim energy density is mathematically irrelevant.
• DCancel the energy storage project.

A radioactive Uranium-238 nucleus (atomic number 92) undergoes alpha decay. What are the mass number and atomic number of the resulting daughter nucleus (Thorium)?

• AMass number 234, atomic number 90.
• BMass number 238, atomic number 93.
• CMass number 234, atomic number 92.
• DMass number 242, atomic number 94.

Which periodic trend correctly describes electronegativity across the main group elements?

• AIncreases moving left-to-right across a period; decreases moving down a group.
• BDecreases moving left-to-right across a period; increases moving down a group.
• CRemains constant for all elements on the periodic table.
• DIncreases moving down a group; remains constant across periods.

Two point charges (+2 μC and -2 μC) are separated by distance r, exerting an attractive electrostatic force F on each other. If the distance between the charges is doubled to 2r, what is the new electrostatic force?

• A1/4 F (decreases to one-fourth).
• B1/2 F (decreases to one-half).
• C2 F (doubles).
• D4 F (quadruples).

Which meiotic event exchanges genetic material between non-sister chromatids of homologous chromosomes during Prophase I, producing novel allele combinations?

• ACrossing over (genetic recombination).
• BCytokinesis.
• CDNA replication in S phase.
• DNondisjunction.

When blood glucose levels rise after a meal, the pancreas secretes insulin, causing tissue cells to absorb glucose and returning blood sugar to normal set point. What type of regulatory loop is this?

• ANegative feedback loop.
• BPositive feedback loop.
• CFeed-forward runaway loop.
• DAneuploid mutation loop.

How does the CRISPR-Cas9 genome editing system achieve precise target specificity when modifying a specific gene sequence in eukaryotic cells?

• AA synthetic guide RNA (gRNA) sequence binds to a complementary target DNA sequence, direc…
• BCas9 enzymes randomly cut all cellular DNA strands simultaneously.
• CCRISPR uses radio waves to alter nuclear protons.
• DCas9 converts amino acids into viral membrane lipids.

Why is Uranium-Lead radiometric dating preferable to Carbon-14 dating for determining the absolute age of 3-billion-year-old Precambrian zircon crystals?

• AUranium-238 has a half-life of 4.5 billion years, whereas Carbon-14 half-life (5,730 year…
• BCarbon-14 decays into solid gold after 100 years.
• CZircon crystals contain 100% pure organic carbon.
• DUranium decay rate changes based on atmospheric rain.

Which astronomical factor contributes to long-term Milankovitch climate cycles that drove Quaternary ice age glacial-interglacial oscillations over hundreds of thousands of years?

• ACyclical variations in Earth's orbital eccentricity, axial tilt (obliquity), and axial pr…
• BChanges in the speed of light traveling from the Sun.
• CAsteroid impacts occurring predictably every 100 years.
• DVariations in the Moon's distance caused by ocean tides.

As global temperatures rise, Arctic sea ice melts, exposing dark ocean water that absorbs more solar radiation than reflective ice. This absorption further increases temperature and causes more ice to melt. What type of mechanism is this?

• AA positive feedback loop that amplifies initial warming.
• BA negative feedback loop that restores cold temperatures.
• CA geothermal cooling mechanism.
• DAn atmospheric nuclear fusion reaction.

Civil engineers designing a storm surge barrier system for coastal Puget Sound construct a high-resolution computational fluid dynamics (CFD) model. What is the primary advantage of using CFD computer modeling during design analysis?

• AEngineers can test sea-level rise and extreme storm wave scenarios quickly and safely to…
• BCFD models make physical construction unnecessary.
• CComputer models automatically eliminate sea-level rise.
• DCFD models guarantee zero cost for steel and concrete.

How much thermal energy (Q) is required to raise the temperature of 250 grams of liquid water from 20°C to 60°C? (Specific heat capacity of water c = 4.184 J/g°C).

• A41,840 Joules.
• B10,000 Joules.
• C62,760 Joules.
• D4,184 Joules.

If Reaction 1 (A -> B) has ΔH = -100 kJ/mol and Reaction 2 (B -> C) has ΔH = +30 kJ/mol, what is the overall enthalpy change for Reaction 3 (A -> C)?

• A-70 kJ/mol.
• B-130 kJ/mol.
• C+130 kJ/mol.
• D+70 kJ/mol.

How do hydroelectric generators at Grand Coulee Dam in Washington produce AC electrical current from mechanical water flow?

• AWater turbines spin giant electromagnets inside stationary wire coils, causing a changing…
• BWater molecules convert directly into free electrons inside copper cables.
• CTurbines burn water to produce static electric sparks.
• DGravity pushes air molecules into electrical outlets.

A toxic chemical binds to an enzyme's allosteric site (away from the active site), altering the 3D shape of the active site so substrate molecules can no longer bind efficiently. How is this inhibitor classified?

• AA non-competitive inhibitor.
• BA competitive inhibitor.
• CA coenzyme activator.
• DA photosynthetic pigment.

Which stage of aerobic cellular respiration generates the vast majority of usable ATP energy using an oxygen-dependent proton gradient across the inner mitochondrial membrane?

• AElectron Transport Chain and Oxidative Phosphorylation.
• BGlycolysis.
• CLactic acid fermentation.
• DCitric Acid (Krebs) Cycle.

Atmospheric nitrogen gas (N2) makes up 78% of air, but plants cannot absorb N2 directly. Which biological organisms perform nitrogen fixation to convert N2 gas into bioavailable ammonium (NH4+)?

• ANitrogen-fixing bacteria living in soil and legume root nodules.
• BHerbivorous mammals like black-tailed deer.
• CPhotosynthetic green algae.
• DFungal mushrooms growing on rotting wood.

Where were heavy elements like Gold (Au), Lead (Pb), and Uranium (U) on Earth originally synthesized in the universe?

• AIn catastrophic supernova explosions and neutron star collisions.
• BInside Earth's molten iron core.
• CIn the upper layers of Earth's atmosphere during thunderstorms.
• DInside commercial nuclear power reactors.

Identical fossils of the freshwater reptile Mesosaurus are found in Permian rock layers in both eastern South America and western Africa. What geological concept explains this fossil distribution?

• ASouth America and Africa were once joined together as part of the supercontinent Pangea.
• BMesosaurus swam thousands of miles across the saltwater Atlantic Ocean.
• CMesosaurus eggs were blown across the ocean by storm winds.
• DSouth America and Africa swap positions every 1,000 years.

What two primary mechanisms contribute to global sea-level rise as Earth's climate warms?

• AThermal expansion of warming ocean water and melting of land-based glaciers and ice sheet…
• BMelting floating Arctic sea ice and increased rainwater falling into oceans.
• CEarth's magnetic field shrinking and pushing ocean basins upward.
• DIncreased underwater volcanic lava eruptions displacing water.

Engineers are evaluating two culvert designs for a roadway crossing a salmon-bearing Washington stream. Design A is a round pipe that is cheap to install ($50,000) but accelerates water velocity, preventing salmon passage. Design B is a wide bottomless arch bridge ($180,000) that preserves natural stream velocity and salmon migration. Which decision aligns with Washington state environmental engineering standards?

• ASelect Design B because ecological criteria (salmon passage compliance) outweigh initial…
• BSelect Design A to minimize initial budget costs regardless of fish passage laws.
• CCancel the roadway project permanently.
• DBuild Design A and poison the stream to eliminate salmon.

Consider the balanced equation: 2 H2 + O2 -> 2 H2O. How many moles of liquid water (H2O) are produced when 4.0 moles of hydrogen gas (H2) react completely with excess oxygen gas?

• A4.0 moles.
• B2.0 moles.
• C8.0 moles.
• D1.0 mole.

Water (H2O, molar mass 18 g/mol) is a liquid at room temperature with a high boiling point (100°C), whereas Hydrogen Sulfide (H2S, molar mass 34 g/mol) is a gas at room temperature (-60°C boiling point). Why does water have a much higher boiling point despite its lower molar mass?

• AWater molecules form strong intermolecular hydrogen bonds between O and H atoms.
• BHydrogen sulfide contains strong covalent triple bonds that lower its boiling point.
• CWater molecules are non-polar and experience zero London dispersion forces.
• DHydrogen sulfide is an ionic compound that decomposes in air.

In a photoelectric effect experiment, high-frequency ultraviolet light shines on a potassium plate, ejecting electrons immediately. Dim red light of low frequency fails to eject electrons no matter how long or bright it shines. What quantum concept does this demonstrate?

• ALight behaves as discrete energy packets (photons) where individual photon energy depends…
• BRed light travels faster than ultraviolet light in a vacuum.
• CElectrons are converted into protons when absorbing light.
• DPotassium metal is transparent to ultraviolet light.

In a human family pedigree, a genetic disorder appears almost exclusively in males. Unaffected mothers pass the trait to 50% of their sons, while affected fathers never pass the trait to their sons. What mode of inheritance is indicated?

• AX-linked recessive inheritance.
• BAutosomal dominant inheritance.
• CY-linked inheritance.
• DMitochondrial maternal inheritance.

All somatic body cells in a human contain the exact same genomic DNA sequence. Why do nerve cells and muscle cells look and function completely differently?

• ADifferent cell types activate and express different specific subsets of genes while silen…
• BNerve cells destroy half of their DNA during development.
• CMuscle cells absorb extra chromosomes from food.
• DNerve cells originate from plant chloroplasts.

In a Washington terrestrial ecosystem, total producer biomass is measured at 5,000 kg per hectare. Using the approximate 10% rule for transfer between trophic levels, what is the expected biomass of secondary consumers (carnivores) in this ecosystem?

• AAbout 50 kg per hectare.
• BAbout 500 kg per hectare.
• CAbout 5,000 kg per hectare.
• DAbout 50,000 kg per hectare.

What observational discovery made by Penzias and Wilson in 1965 provided decisive evidence supporting the Big Bang origin of the universe?

• AThe 2.7 Kelvin Cosmic Microwave Background (CMB) radiation uniformly filling space.
• BFinding solid granite rocks floating in outer space.
• CObserving the Sun transform into a black hole.
• DDiscovering that Andromeda galaxy is moving toward Earth.

How does increased atmospheric CO2 cause ocean acidification, harming shellfish and coral reefs in Washington coastal waters?

• ADissolved CO2 reacts with seawater to form carbonic acid, increasing H+ concentration and…
• BCO2 absorbs ocean salt and converts seawater into fresh water.
• CCO2 turns seawater into solid sulfuric acid lava.
• DCO2 prevents light from entering the ocean by turning water black.

Comet Halley orbits the Sun in a highly elongated elliptical orbit. According to Kepler's Second Law of Planetary Motion, where in its orbit does Comet Halley travel at its maximum orbital speed?

• AAt perihelion (the point closest to the Sun).
• BAt aphelion (the point farthest from the Sun).
• CSpeed is completely constant throughout the entire elliptical orbit.
• DAt the midpoint between the two orbital foci when perpendicular to the Sun.

When evaluating the sustainability of electric vehicles compared to gasoline vehicles, why do engineers perform a comprehensive Life Cycle Assessment (LCA)?

• ATo measure total environmental impact across all phases, from raw lithium mining to batte…
• BTo ignore mining and focus exclusively on tailpipe emissions during driving.
• CTo guarantee that electric vehicles cost zero dollars to purchase.
• DTo eliminate the need for battery recycling programs.

A weather balloon filled with 10.0 cubic meters of Helium gas at sea level (pressure 1.0 atm, temperature 290 K) rises into the stratosphere where pressure drops to 0.1 atm and temperature drops to 218 K. What is the new volume of the balloon?

• A75.2 cubic meters.
• B100.0 cubic meters.
• C7.5 cubic meters.
• D1.0 cubic meter.

When 50 mL of 1.0 M Hydrochloric Acid (HCl) is mixed with 50 mL of 1.0 M Sodium Hydroxide (NaOH) in a beaker, what two products are formed?

• ASodium Chloride (NaCl salt) and Water (H2O).
• BChlorine gas (Cl2) and Hydrogen gas (H2).
• CSodium metal (Na) and Hydrochloric acid vapor.
• DCarbon dioxide (CO2) and Ammonia (NH3).

Which type of electromagnetic radiation possesses the shortest wavelength and highest photon energy?

• AGamma rays.
• BRadio waves.
• CInfrared light.
• DMicrowaves.

In human ABO blood groups, a parent with blood type A (genotype IA i) and a parent with blood type B (genotype IB i) have a child with blood type AB (genotype IA IB). What inheritance pattern does the AB phenotype demonstrate?

• ACodominance (both IA and IB alleles are fully expressed).
• BIncomplete dominance (a blended intermediate pink blood type).
• CSex-linked recessive inheritance on the Y chromosome.
• DPolygenic environmental mutation.

Pancreatic beta cells package insulin protein into membrane-bound vesicles, which fuse with the plasma membrane to release insulin into the bloodstream. What cell transport mechanism is being used?

• AExocytosis.
• BEndocytosis.
• CSimple passive diffusion.
• DOsmosis.

Sea otters along the Washington coast feed on sea urchins. When sea otters were hunted to near extinction, sea urchin populations exploded, overconsuming kelp forests and destroying habitats for dozens of fish species. What role do sea otters play in this coastal ecosystem?

• AA keystone species whose presence maintains ecosystem biodiversity.
• BAn invasive alien species that destroys natural habitats.
• CA primary producer that manufactures kelp from sunlight.
• DA decomposer that breaks down rock minerals.

The Hawaiian Island chain consists of volcanoes that get progressively older moving northwest away from the active Big Island of Hawaii. What geological mechanism formed this linear island chain?

• AThe Pacific Plate moving northwest over a stationary deep mantle hotspot plume.
• BA convergent subduction boundary wrapping around the Pacific Ocean.
• CA transform fault sliding back and forth every million years.
• DGlacial ice sheets dragging volcanoes across the ocean floor.

Why are most of Earth's major hot deserts (such as the Sahara and Australian Outback) concentrated around 30° North and 30° South latitudes?

• ADry air descending from the upper atmosphere in Hadley cells creates persistent high-pres…
• BEquatorial solar radiation strikes only 30° latitudes.
• CThe oceans surrounding 30° latitudes contain zero water.
• DEarth's magnetic field repels rain clouds away from 30° latitudes.