14-1 – Matter and Thermal Energy Classifying Matter

14-1 – Matter and Thermal Energy Kinetic Theory of Matter All matter is composed of tiny particles These particles are in constant, random motion The particles collide with each other and with the walls of any container in which they are held The amount of energy that the particles lose from these collisions is negligible.

14-1 – Matter and Thermal Energy Kinetic Molecular Theory Explains why matter changes states Matter changes states due to gain or loss of energy Explains why a particular state behaves as it does Objects expand when heated Explains why the temperature of a substance increases as you heat it Temperature of an object is a measure of the average kinetic theory of a substance

14-1 – Matter and Thermal Energy Anything with mass that takes up space (volume) is matter. Exists in 4 states Solid Liquid Gas Plasma

14-1 – Matter and Thermal Energy Solid: The particles of a solid are in a tight, fixed position. Since the particles in solids are not free to move around they vibrate just a little. Solids have a set volume and a set shape.

14-1 – Matter and Thermal Energy Liquid: The particles of a liquid are close together, but they are not in a neat arrangement like in a solid. They have enough space to slide past each other. Liquids have a set volume but no set shape.

14-1 – Matter and Thermal Energy Gas: The particles of a gas have a lot of space between them. They move fast and in no order. The volume of gas also increases as temperature increases. Gasses have no set volume and no set shape.

14-1 – Matter and Thermal Energy Plasma: Contains particles that are positively and negatively charged. Atoms begin to lose electrons, creating charged particles that move freely. Plasma, like a gas, has no set volume or shape and can be found in stars, Plasma TVs, and neon signs.

14-1 – Matter and Thermal Energy Changes of state Melting point – Melting – Heat of fusion – Freezing point – Freezing -

14-1 – Matter and Thermal Energy Changes of state Boiling point – Evaporation – Heat of vaporization – Condensation - Sublimation-

14-1 – Matter and Thermal Energy Heating Curves A graph of temperature vs. time for heating a substance

15-1 – Classification of Matter Pure Substances Elements – Element and atom are not the same Periodic Table of Elements Compounds – Made from combined elements

15-1 – Classification of Matter

15-1 – Classification of Matter Bromine (Br2) and Oxygen (O2) exist naturally as molecules. Each molecule consists of two atoms bonded together. Even though it is made of molecules it is still an element because it contains only one type of atom.

15-1 – Classification of Matter Element or Compound?? H20 Copper (Cu) C6H12O6 NaCl Oxygen (O2) Sodium (Na)

15-1 – Classification of Matter Mixtures- Heterogeneous Mixtures – Homogeneous Mixtures- Solutions-

15-1 – Classification of Matter Classify the following as an element, compound, or mixture. If mixture, make sure to label homogenous or heterogeneous. 1) soda 4) Nitrogen (N) 2) water (H20) 5) NH4 3) gravel 6) a taco

15-2 – Properties of Matter Physical properties Physical properties are characteristics of a substance that can be measured without changing the identity of the substance. Appearance (for example, color or shape) Odor Melting point and boiling point Density Hardness Ductility and Malleability (ability to change shape) Solubility Electrical and thermal conductivity Magnetism

15-2 – Properties of Matter Chemical properties characteristics of a substance that describe the ways it can react to form new materials. Chemical properties cannot be measured or studied without changing the composition of the substance. Flammability and other tendencies to react with oxygen Reaction with acids and bases Reaction with water Decomposition caused by light or heat Tendency to corrode

15-2 – Properties of Matter Physical Changes Physical changes are changes that do not result in the formation of a new substance. The substance is still the same because chemical bonds have not been broken or formed, and so the atoms of the molecules are still connected in the same way.

15-2 – Properties of Matter Chemical Changes referred to as chemical reactions. always produce new substances with properties that are typically very different from those of the reactants. some clues that can indicate a chemical change has occurred. visible flames color change bubbling or fizzing smoke heat or light given off formation of a substance in a different state (for example, a solid from two liquids) Of these observations, seeing flames is the only sign that always indicates a chemical change. All of the others can sometimes be the result of a physical change.

A tree burns to form ashes Event Physical Chemical Cutting your hair Mixing sugar and water Baking soda reacts with baking soda and forms a gas A piece of paper is crumpled up Baking cookies An aspirin is crushed into a powder A tree burns to form ashes Methanol is burned and leaves a residue Water freezes to ice A piece of metal is bent in half

15-2 – Properties of Matter Law of Conservation of Mass Mass cannot be created or destroyed To put the law another way, the amount of matter before the change equals the amount of matter after the change.

15-2 – Properties of Matter The law of conservation of mass is also true for physical changes. An ice cube has the same mass as the water produced when it melts. In other cases, conservation of mass is less obvious. If we think about it, we can usually explain cases in which the law of conservation of mass seems to have been violated.