A scientific model stating that all matter is composed of tiny particles (atoms, molecules, or ions) that are in constant motion, with the degree of motion and the spacing between particles increasing from solids to liquids to gases as energy is added.
Everything is made of tiny particles that are always moving. How fast they move and how tightly they're held together explains solids, liquids, and gases.
Showing a random 20 of 50 problems.
Example 1
challenge
Use particle theory to explain all three: why solids have fixed shape and volume, liquids have fixed volume but not shape, and gases have neither.Compare all three states: shape, volume, and particle arrangement
Example 2
medium
Using particle theory, explain why a solid has a fixed shape but a gas does not.Solid has fixed shape; gas does not — compare particle arrangements
Example 3
easy
Why can gases be compressed according to particle theory?
Example 4
medium
A student says 'when wax melts, the wax particles themselves change.' Use particle theory to correct this claim.
Example 5
medium
Two identical balloons hold helium and the same volume of carbon dioxide at the same temperature and pressure. Compare the number of particles in each.
Example 6
challenge
A sealed syringe of air is plunged underwater. The plunger is pushed in halfway. Using particle theory, explain what happens to (a) particle count, (b) particle speed, and (c) pressure inside.
Example 7
easy
How does particle motion change when a substance is heated?
Example 8
medium
Explain why solids generally have higher density than gases of the same substance, using particle theory.Solid vs gas: compare particle packing and density
Example 9
easy
State the four main points of the particle theory of matter.
Example 10
easy
What kind of motion do particles in a solid have?
Example 11
medium
Why is it easier to compress a sponge full of air than a sponge full of water?
Example 12
easy
When ice melts, do the water particles themselves change, or just their arrangement?When ice melts, do the particles change or just their arrangement?
Example 13
easy
In which state of matter are the particles packed most closely together?Which state has particles packed most closely together?
Example 14
easy
What is between gas particles, according to particle theory?
Example 15
medium
As a liquid cools toward becoming a solid, how does the average kinetic energy of its particles change?As a liquid cools and freezes, how does particle kinetic energy change?
Example 16
hard
A scuba tank is filled with compressed air. According to particle theory, how can the same number of air particles fit in a tank that is much smaller than a balloon holding the same air at normal pressure?
Example 17
medium
Use the particle theory to explain why a gas fills its entire container, while a liquid settles to the bottom.
Example 18
medium
Explain why a metal spoon left in hot soup gets hot at the handle, using particle theory.
Example 19
medium
Use particle theory to explain why you can smell perfume from across a room.
Example 20
easy
In which state do particles have the most kinetic energy: solid, liquid, or gas (at the same substance, increasing temperature)?Which state has the most kinetic energy?