Solids, liquids and gases as moving particles
Grade 8 Science Worksheet - Building Confidence
Circle the best answer, or write your answer on the line.
The hot plate adds energy at a steady rate. Ari heats ice on a hot plate. From the first reading of 0 °C to the last, how many minutes pass?
The teacher adds energy at a steady rate. A teacher warms crushed ice in a beaker. How many minutes pass from the first reading of 0 °C to the last, Esme?
Longer motion lines mean faster particles. Jun compares two models of the same gas. Which statement does the table support?
- The two boxes are at one temperature, since both hold 8 particles
- Box A is warmer, since the short lines show particles moving slowly
- Box B is warmer, since its particles move faster on average
- Box B is warmer, since its particles are larger than box A's particles
Longer wiggle lines mean faster vibrating. Kira compares two models of one solid. Which statement does the table support?
- Box B is warmer, and it is still a solid since its particles stay in rows
- Box B is warmer, and its particles have swelled, since heat makes particles grow
- Box B is warmer, since heat has added new particles between the rows
- The two boxes are at one temperature, since both show particles in neat rows
Longer motion lines mean faster particles. Luz compares two sealed boxes of gas. Which box pushes harder on its walls? Use the table.
- Box B, since heating has added more particles to the box
- Box A, since slower particles stay near the walls and press longer
- Box B, since faster particles hit the walls harder and more often
- Neither, since both boxes hold 8 particles and the pushes are equal
Read this first
Melting and boiling points at sea level (reference data)
substance melts at (°C) boils at (°C) Ethanol −114 78 Nitrogen −210 −196 Bromine −7 59 At −100 °C, which substance in the table is a liquid, Noah?
- Ethanol, since −100 °C is above −114 °C and below 78 °C
- Bromine, since −100 °C is below its boiling point of 59 °C
- Bromine, since it is a liquid at room temperature and stays liquid when cold
- Nitrogen, since −100 °C is above its melting point of −210 °C
At 90 °C, what state is each substance in, Pia?
- Both are liquids, since 90 °C is above the melting point of each substance listed
- Water is a gas, since 90 °C is close to 100 °C, and ethanol is a liquid since it melts at −114 °C
- Water is a liquid and ethanol is a gas, since 90 °C is above ethanol's boiling point
- Both are liquids, since 90 °C is below the boiling point of water, which is 100 °C
A drop of dye spreads faster in warm water than in cold water. Which explanation fits the particle model, Ren?
- Warm water particles move faster, so they bump the dye particles around and spread them sooner
- Warm water holds more particles than cold water, so more of them are there to push the dye along
- Warm water particles shrink as they heat up, so the dye particles can slip between them sooner and spread
- Dye particles stop moving in cold water, so they cannot spread until the water has warmed up
A sealed balloon of air shrinks in a freezer. Which explanation fits the particle model, Tala?
- The cold shrinks each air particle, so the same particles take up less room inside the balloon and it gets smaller
- Slower air particles hit the wall less often and less hard, so it shrinks until the pushes balance
- The cold destroys some of the air particles, so less air is left inside the balloon and it gets smaller
- Air particles stop moving in the cold, so they fall to the bottom of the balloon and it collapses
Zee says a solid's particles do not move, so a solid has no thermal energy. Which reply fits the particle model?
- A solid's thermal energy is stored in the empty gaps between its particles, not in the particles themselves
- A solid's particles stay still, and its thermal energy comes from its mass, not from any particle motion
- Solid particles vibrate in place, so they have thermal energy, and warming makes them vibrate faster
- Solid particles slide past one another like those in a liquid, so they move enough to hold thermal energy