What is the Particle Kinetic Model of Matter (PKMM) and how does it explain the melting and boiling points of materials?

Particle Kinetic Model explains phase changes.

• Matter consists of moving particles.

• Energy affects particle motion and states.

• Different substances have varied melting points.

Fill in the blank: When a solid heats up, its particles vibrate faster and eventually break free from their ordered ___ structure to become a liquid.

Lattice

True or False: All particles in a solid remain completely motionless until they are heated.

False. Particles in a solid vibrate but remain fixed in place until heated.

Riddle: I can turn from solid to liquid with warmth, my particles slide and dance, breaking free from their form. What am I?

A melting solid (e.g., solder)

What factors influence the boiling point of a material, particularly at different altitudes?

Boiling point is altitude dependent.

• Pressure decreases with altitude.

• Lower pressure lowers boiling point.

• Energy needed to boil reduces.

What happens to the kinetic energy of particles when a material is heated?

When a material is heated, the kinetic energy of its particles increases, causing them to vibrate or move faster.

Fill in the blank: Zinc melts at ___ °C due to its weaker attractive forces between particles.

419.5

True or False: The temperature of a material is a direct measure of the heat content within the particles.

False. The temperature reflects the average kinetic energy of the particles, not the heat content.

What is the process called when surface molecules of a liquid gain enough energy to escape into the air?

Evaporation.

Riddle: I am a process where bubbles form and rise, creating a dance in the liquid before bursting. What am I?

Boiling.

Explain why copper has a higher melting point than zinc.

Copper has a higher melting point than zinc.

• Stronger atomic bonds.

• Higher energy needed to melt.

• Denser atomic structure.

Fill in the blank: A liquid boils when its particles move fast enough to create vapor bubbles with pressure equal to the ___ pressure on the liquid’s surface.

Atmospheric

How does atmospheric pressure affect the boiling point of a liquid?

Atmospheric pressure pushes down on the surface of the liquid, making it harder for molecules to escape, thus affecting the boiling point.

Short Answer: Define boiling in terms of particle movement and pressure.

Boiling involves particle movement and pressure.

• Particles gain kinetic energy.

• Vapor bubbles form in liquid.

• Pressure equals atmospheric pressure.

What occurs at the molecular level when a liquid begins to boil?

Liquid boils when heated.

• Particles gain kinetic energy.

• Vapor bubbles form and rise.

• Pressure balance is achieved.

What happens to the temperature of boiling water during the boiling process, and why does this occur?

Boiling water temperature remains constant.

• Fastest molecules escape as vapor.

• Kinetic energy is lost to vapor.

• Average kinetic energy stays steady.

Boiling points of water depend on altitude because ___ affects atmospheric pressure.

Boiling points depend on altitude.

• Altitude affects pressure levels.

• Lower pressure means lower boiling.

• Kinetic energy needed decreases.

True or False: Water boils at 100°C at all altitudes.

False. Water boils at lower temperatures at higher altitudes due to decreased atmospheric pressure.

Fill in the blank: In sealed systems like car radiators, increased pressure ___ the boiling point of water.

Raises

Riddle: I am a process where the fastest molecules escape, keeping my surroundings at the same temperature. What am I?

Boiling

At sea level, the boiling point of water is ___ degrees Celsius.

100

How does atmospheric pressure influence the boiling point of water at high altitudes?

Atmospheric pressure lowers boiling point.

• Pressure affects vapor formation.

• Less heat energy needed.

• Boiling point decreases at altitude.

What is the consequence of boiling water at a high altitude, such as on a mountain?

Water boils at lower temperature.

• High altitude reduces boiling point.

• Cooking times increase due to lower heat.

• May affect food texture and safety.

What is the primary mechanism of heat transfer that involves particle vibrations in a material?

Conduction is the primary mechanism of heat transfer that involves particle vibrations in a material.

Thermal conductors are materials that transfer heat energy ___ from a hot region to a colder one.

Quickly