U NIT 5: P HYSICAL B EHAVIOR OF M ATTER

U NIT O VERVIEW In this unit you will learn about matter and energy, and how they interact in the universe. Whenever matter and energy interact, changes in matter occur.

M ATTER VS. E NERGY MatterEnergy -Matter is anything that has Mass and Volume - All physical objects or any substance composed of atoms - Measured in Grams -Energy is the ability to do work - Is measured in Joules or Kilojoules (J or kJ) - Can be either Potential or Kinetic

This is energy that is being stored, usually observed in objects that are not moving Something with a lot of stored energy has the “ potential ” to do a lot of work Example) A child sitting at the top of a slide… P OTENTIAL E NERGY

This is energy in motion All objects possess some amount of kinetic energy (even an object at rest has movement in its particles) Example) A child going down a slide… K INETIC E NERGY

D IFFERENT TYPES OF ENERGY … Light  is waves, visible or invisible Electrical  involves moving electrons Heat  movement of molecules Chemical  is contained in foods Nuclear  responsible for the sun Sound  waves/vibrations of molecules Mechanical  involves moving objects Magnetic  opposing poles

L AW OF C ONSERVATION OF E NERGY Energy, like matter, is neither created nor destroyed, rather it is converted.

In equations we use the symbol “q” to represent heat. ΔH represents change in heat energy. Heat always travels from warm areas to cool areas. 3 ways heat energy can be transferred: U NDERSTANDING H EAT F LOW 1) Conduction 2) Convection 3) Radiation

Heat energy is a raw measure of heat in Joules or Kilojoules Temperature is a measure of the average kinetic energy in the particles of matter Potential energy cannot be measured by temperature… H EAT E NERGY V S. T EMPERATURE

Endothermic – Chemical process where energy is absorbed heat is a reactant q or ΔH is positive number like +350 kJ Exothermic – Chemical process where energy is released Heat is a product q or ΔH is a negative number like kJ K EY T ERMS R EVIEW *In all changes in matter energy is either released or absorbed*

Sometimes chemical reactions can’t occur on their own So… They need a little spark of energy to start the reaction This is called Activation Energy A CTIVATION E NERGY * Even some spontaneous reactions require activation energy

The energy of particles of matter relate to the phase/state of matter (solid, liquid, or gas) Energy change can cause phase changes E NERGY AND P HASE C HANGES