Matter and Thermal Energy Quiz

Matter and Thermal Energy

• Matter exists in different states: solid, liquid, gas, and plasma.
• Each state has unique properties related to the arrangement and movement of its particles.

Gas State

• Kinetic theory explains gas behavior.
• Gas particles are widely separated with lots of empty space.
• Gas particles are in constant random motion.
• Collisions between gas particles are elastic.
• Gas pressure is caused by collisions between gas particles and the container's walls.

Liquid State

• Liquid particles are constantly moving but less quickly than gas particles.
• Liquid particles have less kinetic energy than gas particles.
• Liquid particles are more tightly packed than gas particles, but less so than solid particles.
• Liquids cannot be compressed.
• Liquids take the shape of their container.

Solid State

• Solids have a definite shape and volume.
• Solid particles are closely packed together.
• Solid particles vibrate, but do not have much kinetic energy.
• Solids cannot be compressed or change shape easily.

Crystalline and Amorphous

• Crystalline solids have particles arranged in regular geometric patterns.
• Crystalline solids have a definite melting point.
• Examples include salt, sugar, and sand.
• Amorphous solids do not have a regular geometric pattern.
• Amorphous solids have no definite melting point.
• They soften gradually before becoming liquid.

Thermal Energy in Particles

• Thermal energy is the total energy of the particles in a material.
• Thermal energy includes kinetic and potential energy of the particles.
• Temperature is the average kinetic energy of the particles in a substance.
• In solids, strong attractions between particles hold them in place.
• Solids have a definite shape and volume.

Changes in State

• Adding thermal energy to a system causes some particles to move faster.
• Energy is transferred between particles during changes of state.
• Melting occurs when kinetic energy overcomes attractive forces, breaking the crystalline structure.
• Melting point is the temperature at which a solid becomes a liquid.
• Heat of fusion is the energy needed to change a substance from solid to liquid at its melting point.
• Freezing is the opposite of melting, energy is removed and solid forms.
• Freezing point is the temperature at which a liquid becomes a solid.

Vaporization and Condensation

• Vaporization is the process of a liquid becoming a gas.
• Particles must move fast enough to overcome the attractions between them.
• Evaporation occurs at the surface of a liquid.
• Boiling occurs throughout the liquid at a specific temperature.
• Condensation is the process of a gas becoming a liquid.
• Boiling point is the temperature at which the vapor pressure of a liquid equals the external pressure.
• Heat of vaporization is the energy required to change a substance from liquid to gas.

Sublimation

• Solids can directly change into gases (or vice-versa) under certain pressures: this is sublimation
• Dry ice (solid carbon dioxide) sublimates.

Heating Curves

• Heating curves show how temperature changes over time as thermal energy is added.
• At melting/boiling points, thermal energy is used to overcome the attractive forces causing temperature to remain constant.

Plasma State

• Plasma is a state of matter where matter has enough energy to overcome the attractions between particles and within atoms.
• Atoms in plasma collide with great force,
• Examples include lightning, stars, and fluorescent lights.
• Plasma is the most common state of matter in the universe.

Fact About Plasma State

• Plasma is an ionized gas.
• Electrons are ionized and move independently of the atoms.
• Much of the mass of the universe is in plasma state.

Thermal Expansion

• Temperature increase causes particles to move faster and further apart, expanding volumes of substances.
• Temperature drop causes substances to contract.
• Thermometers use thermal expansion of liquids to measure temperature.

Hot Air Balloons

• Thermal expansion of air increases volume without changing mass.
• This results in decreased density, making hot air balloons rise.

Water as an Exception

• Water expands when freezing, unlike other substances.
• This is due to the unique structure of water molecules that align unevenly making empty spaces when frozen.
• Water's exceptional behavior is crucial for life on Earth.

Solid or Liquid?

• Amorphous solids soften and melt over a range of temperatures.
• Liquid crystals flow during melting without losing their ordered arrangement.