Heat and States of Matter Chapter 9: Heat and States of Matter Section 2: States of Matter

Four States of Matter SOLID STATE 2 The particles of a solid are packed closely together and are constantly vibrating in place. The attractions between particles are strong and solids have a fixed volume and shape.

States of Matter 2 LIQUID STATE The attractive forces are strong enough to cause particles to cling together. Liquids have a definite volume, but not a definite shape.

States of Matter 2 GAS STATE In a gas the forces between particles are so weak that the particles no longer cling together. Gases do not have a definite shape or volume.

States of Matter 2 Plasma State The most common state of matter in the universe is the plasma state. PLASMA is matter consisting of positively and negatively charged particles and does not have a definite shape or volume.

Changing States Melting 2 States of Matter 2 Changing States Melting The temperature at which a solid begins to melt is its melting point. The amount of energy required to change 1 kg of a substance from a solid to a liquid at its melting point is known as the heat of fusion.

States of Matter 2 Freezing The heat of fusion is also the energy released when a liquid freezes. The attractive forces are strong enough that the particles form an ordered arrangement.

Vaporization 2 Vaporization occurs as liquid changes into a gas. States of Matter 2 Vaporization Vaporization occurs as liquid changes into a gas. Vaporization that occurs at the surface of a liquid is called evaporation. Evaporation causes the temperature of the liquid to decrease. Can you explain this?

States of Matter 2 Boiling The boiling point of a liquid is the temperature at which the pressure of the vapor in the liquid is equal to the external pressure acting on its surface. The heat of vaporization is the amount of energy required for 1 kg of the liquid at its boiling point to become a gas.

States of Matter 2 CONDENSATION The HEAT OF VAPORIZATION is also the amount of energy released during condensation. This graph shows the temperature change of water as thermal energy is added.

What about during evaporation? States of Matter 2 CONDENSATION The average kinetic energy of the water molecules doesn’t change. The temperature remains constant during melting. What about during evaporation?

States of Matter 2 CONDENSATION of the gas increases as energy is added. After the liquid water has changed completely into a gas, the temperature

THE THERMAL EXPANSION OF MATTER States of Matter 2 Thermal Expansion THE THERMAL EXPANSION OF MATTER The increased separation between the particles results in the expansion of the object and the size of the object increases. When a material cools, the particles in the material move more slowly and become closer together.

THERMAL EXPANSION OF LIQUIDS States of Matter 2 THERMAL EXPANSION OF LIQUIDS The forces between the particles in liquids are weaker than the forces between the particles in a solid. The same temperature increase usually causes liquids to expand much more than solids.

THERMAL EXPANSION OF GASES States of Matter 2 THERMAL EXPANSION OF GASES In a gas, the forces between particles are much weaker than they are in liquids. Gases expand even more than liquids for the same increase in temperature.

Section Check 2 Question 1 _________ is a state of matter consisting of positively and negatively charged particles that exists where the temperature is extremely high. A. Gas B. Liquid C. Plasma D. Solid

Section Check 2 Answer The answer is C. Plasma is found in the Sun, stars, lightning bolts and neon lights.

Section Check 2 Question 2 Most __________ materials have a specific type of geometric arrangement. A. gaseous B. inert C. liquid D. solid

Section Check 2 Answer The answer is D. The particles in most solids align themselves in ordered geometric patterns.

Section Check 2 Question 3 The amount of energy required to change 1 kg of a substance from a solid to a liquid at its melting point is known as the _______. A. heat of energy B. heat of fusion C. heat of melting D. heat of vaporization

Section Check 2 Answer The correct answer is B. Heat of fusion causes an ice cube to become liquid water.