Digital ACT Practice Questions

Two paleontologists debate the primary cause of the Cretaceous-Paleogene (K-Pg) mass extinction: Paleontologist 1 asserts that an asteroid impact 66 million yea...

Consider the exothermic synthesis of ammonia in a closed container: N2(g) + 3 H2(g) 2 NH3(g) + 92 kJ. A chemical engineer measures ammonia yield at equilibrium ...

A biology student recorded the rate of cellular respiration in Baker's yeast suspended in varying sucrose concentrations at 25°C: - 0% sucrose: 0.2 mL CO2/min -...

Physics students measured the period T of a pendulum while varying string length L and bob mass M: Experiment 1 (M = 100 g fixed): - L = 0.25 m: T = 1.00 s - L ...

A geophysics team studied seismic P-waves (compressional) and S-waves (shear) traveling through Earth's interior: - P-waves travel through both solids and liqui...

Students tested the electrical conductivity of four aqueous solutions: - Solution 1: 0.1 M NaCl -> 10,800 uS/cm - Solution 2: 0.1 M C12H22O11 (sucrose) -> 12 uS...

A physics lab applied varying tensile forces to a steel spring and measured the resulting displacement x from equilibrium: - Force = 2.0 N: Displacement = 4.0 c...

Agronomists monitored soybean net photosynthesis rate (umol CO2/m^2/s) under different atmospheric CO2 concentrations at constant light intensity: - 200 ppm: 11...

In a calorimetry lab, 100.0 g metal cylinders heated to 100.0°C were placed into insulated cups containing 100.0 g of water at 20.0°C: - Lead (c = 0.129 J/g°C):...

A botany student analyzed spinach leaf pigments using paper chromatography with petroleum ether solvent: - Solvent front distance: 10.0 cm - Carotene: 9.5 cm (R...

Potato tuber cores (initial mass 5.00 g) were immersed in sucrose solutions for 2 hours: - 0.0 M sucrose: Final mass = 5.82 g (+16.4%) - 0.2 M sucrose: Final ma...

The effusion times for 100 mL of four gases through a pinhole at 298 K were recorded: - Gas 1 (He, 4 g/mol): 10.0 s - Gas 2 (CH4, 16 g/mol): 20.0 s - Gas 3 (N2,...

A stationary microphone recorded sound frequencies from a 500 Hz siren moving at various velocities toward the microphone: - 0 m/s: 500 Hz - 10 m/s: 515 Hz - 20...

Identical 1.000-meter metal rods were heated from 20°C to 120°C (delta T = 100°C): - Invar: Elongation = 0.12 mm - Steel: Elongation = 1.20 mm - Copper: Elongat...

A chemistry lab added calcium chloride (CaCl2) to 1.0 kg of water and measured freezing points: - 0.0 mol CaCl2: 0.00°C - 0.5 mol CaCl2: -2.79°C - 1.0 mol CaCl2...

Physicists irradiated a cesium metal plate with photons of various frequencies: - Frequency = 4.0 x 10^14 Hz: Kinetic energy of ejected electrons = 0.00 eV (no ...

A capacitor in an RC circuit discharges through a resistor. Voltage across capacitor was recorded: - 0 s: 12.0 V - 2 s: 7.3 V - 4 s: 4.4 V - 6 s: 2.7 V - 8 s: 1...

Students mixed 50 mL of 1.0 M HCl with 50 mL of 1.0 M NaOH in a coffee cup calorimeter: - Initial temperature: 21.0°C - Final temperature: 27.8°C - Calculated d...

Tracers measured groundwater contaminant plume speed in two aquifer formations: - Formation 1 (Coarse Gravel): Velocity = 14.5 m/day - Formation 2 (Fine Silt): ...

A physics acoustics team measured the speed of sound through four media at 20°C: - Air: 343 m/s - Helium: 965 m/s - Water: 1,482 m/s - Steel: 5,960 m/s Sound tr...

E. coli was cultured in nutrient broth at 37°C. Optical density at 600 nm was recorded: - 0 hr (Lag): OD = 0.05 - 2 hr (Log): OD = 0.22 - 4 hr (Log): OD = 0.88 ...

A 0.5 kg mass on a string rotates in a horizontal circle of radius 1.0 m at various linear velocities: - v = 2.0 m/s: Tension = 2.0 N - v = 4.0 m/s: Tension = 8...

A chemist compared 50 mL of unbuffered water to 50 mL of 0.1 M phosphate buffer (initial pH 7.00): - Adding 1.0 mL of 1.0 M HCl to water: pH drops to 1.70 - Add...

Oceanographers mapped alternating normal and reversed magnetic stripes across the Mid-Atlantic Ridge: - The magnetic anomaly pattern on the west side of the rid...