Particle model of matter Transitional Reasoning Practice

Questions

1. 1.

   A student investigates the mechanical response of a solid iron bar at constant room temperature. The student observes that pushing inward on both ends with a hydraulic press produces no measurable reduction in length, and pulling outward on both ends produces no measurable elongation. Based on the particle model of matter, which statement best explains why the solid resists both compression and extension?

   • A) The individual iron particles shrink when pushed together and expand when pulled apart, keeping the total volume of the bar constant.
   • B) The particles are completely stationary in a solid lattice, so mechanical forces cannot overcome their lack of kinetic energy.
   • C) Gravitational attraction between neighboring iron particles is strong enough to resist any externally applied pushing or pulling forces.
   • D) At the equilibrium spacing between adjacent particles, attractive and repulsive forces balance, generating strong repulsion if forced closer and strong attraction if pulled apart.
2. 2.

   A student fills a dry glass beaker with ice water and leaves it on a laboratory bench at room temperature. After several minutes, tiny liquid droplets appear on the dry outer surface of the beaker, even though the beaker is completely sealed at the top and has no cracks. Based on the particle model of matter, which statement correctly explains the formation of these droplets?

   • A) Water particles inside the beaker shrink under the cold conditions and diffuse outward through microscopic pores in the glass.
   • B) Cold glass destroys the kinetic energy of surrounding air molecules, causing individual gas particles to expand until they become visible as droplets.
   • C) Nitrogen and oxygen particles in the air lose their repulsive forces upon contact with the cold surface and chemically transform into water particles.
   • D) Gaseous water particles in the surrounding air transfer kinetic energy to the cold glass, allowing attractive forces to pull them together into a liquid.
3. 3.

   A student places an airtight, sealed container holding a block of pure ice onto a digital balance, which records a mass of 250.0 g. After the ice melts completely into liquid water at room temperature, the student observes that the volume of the substance has decreased slightly, yet the balance still reads exactly 250.0 g. Based on the particle model of matter, which statement best explains why the mass remains unchanged despite the change in state and volume?

   • A) The thermal energy absorbed during melting adds mass to individual particles, precisely compensating for the reduction in volume.
   • B) The individual particles shrink in size as they warm up, while their total count increases to keep the overall mass identical.
   • C) The attractive forces between particles weaken, which allows the surrounding air pressure to maintain a constant downward gravitational force.
   • D) The phase change alters only the arrangement and spacing of the particles, while the total number and individual mass of the particles remain strictly conserved.
4. 4.

   Two cotton wool plugs, one soaked in concentrated ammonia solution and the other in concentrated hydrochloric acid, are inserted simultaneously into opposite ends of a long, horizontal glass tube at uniform room temperature. After several minutes, a distinct white ring of solid ammonium chloride forms inside the tube, appearing significantly closer to the hydrochloric acid plug than to the ammonia plug. Based on the particle model of matter, which statement correctly explains this observation?

   • A) Ammonia particles experience a repulsive force from the cotton plug that propels them with greater initial momentum along the tube.
   • B) Hydrochloric acid particles lose their kinetic energy through collisions with air particles, causing them to decelerate and come to rest sooner.
   • C) Ammonia particles have a smaller mass than hydrogen chloride particles and therefore move with a higher average speed at the same temperature, covering a greater distance before reacting.
   • D) Hydrochloric acid particles possess larger individual particle volumes that create greater friction against the inner walls of the tube, slowing their advance.
5. 5.

   A student heats a pure crystalline solid in an insulated container at a constant rate. A digital temperature sensor records that while the substance melts into a liquid, its temperature remains strictly constant at 55 °C for several minutes despite the continuous supply of heat. Based on the particle model of matter, which statement correctly explains why the temperature does not rise during this process?

   • A) The absorbed thermal energy causes individual particles to decrease in size and mass so they can slip past one another.
   • B) The particles radiate the added thermal energy back out into the surroundings until all rigid bonds are completely broken.
   • C) The average kinetic energy of the particles steadily decreases during melting, counteracting the continuous influx of heat.
   • D) The absorbed thermal energy is used to overcome the attractive forces holding particles in fixed positions rather than increasing their average kinetic energy.
6. 6.

   A student transfers a 50 mL sample of a pure substance from a tall, narrow graduated cylinder into a wide, flat-bottomed glass bowl at constant room temperature. The student observes that the substance immediately flows to adapt to the shape of the bowl, yet its total measured volume remains exactly 50 mL. Based on the particle model of matter, which statement best explains both of these observed properties?

   • A) The particles overcome all attractive forces to move entirely independently, which allows the sample to adopt the container's shape while preserving its volume.
   • B) The particles can slide past one another because intermolecular forces do not hold them in fixed positions, while remaining closely packed due to persistent attractive forces.
   • C) The individual particles change their own shapes to conform to the container boundaries, while their internal mass prevents any change in total volume.
   • D) The particles remain locked at fixed lattice positions, but the entire lattice network tilts and fractures under gravity to fill the base of the container.
7. 7.

   A rigid, sealed steel container holding a fixed quantity of dry air is connected to a digital pressure gauge. When the container is submerged in a warm water bath, its internal volume remains unchanged, yet the gauge records a noticeable increase in gas pressure. Based on the particle model of matter, which statement best explains why the gas pressure increases?

   • A) The individual gas particles absorb thermal energy and expand in volume, crowding more tightly against the container walls.
   • B) The added thermal energy causes the gas particles to divide, increasing the total number of particles inside the fixed volume.
   • C) The gas particles gain kinetic energy and move faster, colliding with the container walls more frequently and with greater force.
   • D) The attractive forces between the gas particles and the steel walls strengthen, drawing the particles outward with higher tension.
8. 8.

   A student places a digital thermometer into a shallow, open dish containing a liquid at room temperature. Over time, the student observes that the volume of the liquid gradually decreases through evaporation, while the thermometer records a steady drop in the liquid's temperature below the ambient room temperature. Based on the particle model of matter, which statement correctly explains why this cooling effect occurs?

   • A) Liquid particles absorb cold from the surrounding environment, which causes them to slow down and condense into vapor.
   • B) Every particle in the liquid loses its kinetic energy uniformly until individual particles become light enough to float into the air.
   • C) Attractive forces between the particles steadily increase, which pulls thermal energy out of the liquid as particles escape.
   • D) Particles with the highest kinetic energy overcome intermolecular attractions and escape from the surface, reducing the average kinetic energy of the remaining liquid.
9. 9.

   A student suspends fine smoke particles in a sealed viewing chamber filled with air and observes them through a microscope in a vibration-free room at constant temperature. Under the microscope, each bright speck of smoke moves continuously in an erratic, unpredictable zig-zag path rather than falling straight down or drifting smoothly. Based on the particle model of matter, which statement correctly explains the cause of this erratic motion?

   • A) The smoke particles absorb energy from the microscope illuminator, causing them to propel themselves actively through the air.
   • B) Convection currents within the sealed chamber continuously drag all the smoke particles along circulating fluid paths.
   • C) Invisible air particles in rapid, random motion collide unevenly against opposite sides of each smoke particle.
   • D) Static electrical charges accumulated on the smoke particles produce mutual repulsion that pushes them irregularly apart.
10. 10.

    A student investigates thermal expansion by passing a solid metal sphere through a matching ring at room temperature, noting that it fits through with barely any clearance. After heating the sphere uniformly over a burner for several minutes, the student discovers that it can no longer pass through the ring. Based on the particle model of matter, which statement correctly explains why the sphere expanded?

    • A) The individual metal particles absorbed thermal energy and increased in physical size, causing the entire sphere to enlarge.
    • B) The metal particles absorbed thermal energy and vibrated more vigorously, causing their average spacing to increase without any change in individual particle size.
    • C) Heating generated additional metal particles within the lattice structure, increasing the total mass and volume of the sphere.
    • D) The attractive forces between the metal particles increased significantly, forcing the particles apart to form internal air pockets.
11. 11.

    A student combines 50 mL of water with 50 mL of ethanol in a sealed graduated cylinder at room temperature. After thoroughly mixing the two liquids, the student observes that the total volume of the mixture is 96 mL, even though no liquid evaporated or escaped. Based on the particle model of matter, which explanation best accounts for this observation?

    • A) The individual particles of both liquids shrink in size when they come into contact with one another.
    • B) A fraction of the particles is destroyed as the two substances chemically neutralize each other.
    • C) The particles of the two liquids have different sizes, allowing smaller particles to fit into the spaces between larger particles.
    • D) Attractive forces cause the liquid particles to stop moving entirely and form a tightly locked solid lattice.
12. 12.

    A student places a single drop of concentrated food dye at the bottom of two identical beakers containing equal volumes of undisturbed water: Beaker X at 15 °C and Beaker Y at 75 °C. After two minutes without stirring, the dye has dispersed completely throughout Beaker Y, whereas in Beaker X it remains concentrated near the bottom. Based on the particle model of matter, which statement best explains this observation?

    • A) Individual dye particles expand in size at higher temperatures, forcing surrounding water particles outward.
    • B) Higher temperature increases the average speed of the particles, leading to more frequent collisions that spread the dye faster through the spaces between water particles.
    • C) Warm water completely eliminates the intermolecular forces between particles, allowing the dye particles to convert directly into a gas.
    • D) Thermal energy creates additional dye particles in Beaker Y, generating a steeper concentration gradient that accelerates mixing.
13. 13.

    A student investigates the behavior of trapped air inside a sealed, leak-proof syringe at constant temperature. When the plunger is pushed inward, the volume occupied by the gas decreases from 60 mL to 30 mL. Based on the particle model of matter, which statement correctly explains this observation?

    • A) The individual gas particles shrink in size to fit within the smaller volume.
    • B) The average distance between the gas particles decreases while the particles themselves remain unchanged.
    • C) The total number of gas particles decreases because particles combine into fewer, larger units.
    • D) The empty spaces between the gas particles are eliminated because the particles stop moving.

Answers and step-by-step solutions appear after you finish the test.