PHYSICAL BEHAVIOR OF MATTER TOPIC 4 PHYSICAL BEHAVIOR OF MATTER

Phases of Matter The 3 phases of matter are: solid, liquid & gas. Heat is exchanged during heating, cooling & phase changes. The kinetic molecular theory explains the behavior of gases. Mixtures separate by physical means.

Phases of Matter The solid phase contains matter held in a rigid form. A substance in this phase has a definite volume and shape. Strong attractive forces hold the particles together and true solids have a crystalline structure.

Phases of Matter The liquid phase has particles that are not held together as rigidly as the solid phase. Particles are able to move which prevents the liquids from having a definite shape but are held together with enough attractive forces to give a definite volume.

Phases of Matter The gaseous phase has minimal attractive forces holding them together. Gases have neither a definite shape nor a definite volume, therefore, they will spread out indefinitely unless confined.

Heating & Cooling Curves As temperature increases, kinetic energy increases.

Heating & Cooling Curves Melting, also known as fusion, occurs because the particles have enough kinetic energy to break their bonds.

Heating & Cooling Curves During melting, temperature remains constant even though heat is being added and thus potential energy increases but since the temperature remains constant so does the kinetic energy.

Heating & Cooling Curves Boiling, also known as vaporization, occurs because the particles have even more kinetic energy breaking the liquid bonds.

Heating & Cooling Curves Kinetic energy increases during the heating of a solid, liquid and gas.

Heating & Cooling Curves Potential energy increases and kinetic energy remains constant during melting of a solid and the boiling of a liquid.

Heating & Cooling Curves The reverse of boiling is condensation and the reverse of melting is freezing.

Heating & Cooling Curves Sublimation is when a solid changes directly to a gas and the reverse process is called deposition.

Temperature Temperature is a measure of the average kinetic energy of particles measured in °C or in K and heat flows from higher temperature to lower temperature.

Temperature K = °C + 273 (on RT)

Heat Energy Heat is a measure of the amount of energy transfer and is measured in calories or joules.

Heat Energy The amount of heat given off or absorbed can be calculated using the formula: q = mCΔT; where q is heat measured in Joules, m is mass measured in grams, C is specific heat measured in J/g·K, ΔT is change in temperature measured in °C or K.

Heat Energy The heat of fusion is the amount of heat needed to convert a solid to liquid and the value is 334 J/g found in Table B.

Heat Energy The heat of vaporization is the amount of heat needed to convert a liquid to gas and the value is 2260 J/g found in Table B.

Heat Energy Melting and boiling are endothermic processes, requiring heat; freezing and condensation are exothermic processes, releasing heat.

Behavior of Gases The kinetic molecular theory is a model/theory used to explain the behavior of gases.

Kinetic Molecular Theory Ideas Particles are in constant, random, straight-line motion Particles collide with each other & walls; transfer energy; no net loss

Kinetic Molecular Theory Ideas Particles separated by great distances, therefore, volume by themselves is negligible Particles do not attract each other

The two elements most like a real gas are hydrogen & helium. Behavior of Gases The two elements most like a real gas are hydrogen & helium.

Gases are most ideal at low pressure and high temperature. Behavior of Gases Gases are most ideal at low pressure and high temperature.

Behavior of Gases Avogadro’s hypothesis states that when the volume, temperature & pressure of two gases are the same, they contain the same number of molecules.