Properties and States of Matter Chapters 2 and 3

Classifying Matter Matter  Anything that has mass and takes up space  Either a pure substance or a mixture end

Classifying Matter-Pure Substance Pure Substance  Matter that always has exactly the same make-up  Either an element or a compound  Salt, table sugar, water, gold, aluminum end

Classifying Matter- Pure Substance Element  Something that cannot be broken down into simpler things  Given a 1 or 2 letter symbol on the Periodic Table (C, N, O, Au, Fe)  Carbon, iodine, gold, iron end

Classifying Matter- Pure Substance Compound  Made from 2 or more things and can be broken down into those things  2 or more elements joined in a fixed proportion  Water, table salt, sugar end

Classifying Matter- Mixture Mixtures  Contains 2 or more elements with no fixed make-up Heterogeneous Mixtures  Can identify different parts of the mixture  Does not look the same all the way through  Salad dressing, sand/dirt Homogeneous Mixtures  Substances cannot be distinguished  Looks the same all over  Tap water, Fruit Punch, stainless steel end

Classifying Matter- Mixtures Solutions  When something dissolves and forms a homogeneous mixture  Salt water, Kool-Aid, Sweet Tea Suspension  A heterogeneous mixture that separates into layers over time  Salad dressing, paint, liquid medicines “Shake well before using” end

Physical Properties Physical property  Something that can be observed or measured without changing the material  7 physical properties you need to know end

Physical Properties Viscosity  Liquid’s resistance to flowing  Honey = high water = low Conductivity  Ability to allow heat/electricity to flow  Iron = good rubber = bad Malleability  Solid’s ability to be hammered without shattering  Gold = very glass = not end

Physical Properties Hardness  Ability of something to cut something else  Diamond is the hardest substance on Earth Melting Point  Temp. where a substance goes from a solid to a liquid Boiling Point  Temp. where a substance gores form a liquid to a gas end

Physical Properties Density (D)  A substances’ mass divided by its volume  Measured in either g/mL or g/cm 3 Remember: 1 mL = 1 cm 3 !!!  Things that are more dense will sink, Things that are less dense will float Density (g/mL or g/cm 3 ) mass (g) Volume (mL or cm 3 ) end

Physical Properties A rock has a mass of 12 g. If it has a volume of 50 mL, what is the rock’s density? A block has a density of g/cm 3. If the block has a volume of 56 mL, what is the block’s mass? A graduated cylinder has 13.4 mL of water. When a marble, with a density of 6.2 g/mL, is dropped in the cylinder the water level rises to 34 mL. What is the marble’s mass? end

Using Physical Properties Physical properties are used for:  Identifying a material  Choosing a material for a specific purpose  To separate the substances in a mixture end

Separating Mixtures Filtration  Separates materials based on the size of their particles  Using a coffee filter Distillation  Separates things in solution based on boiling points  Making moonshine end

Chemical Properties Chemical property  A property that produces a change in something’s composition  Something is changing into something else end

Chemical Properties Flammability  Ability to burn in the presence of oxygen  Different elements burn different colors  Think fireworks!!! Reactivity  How quickly something combines with other things end

Physical vs. Chemical Changes Physical Change  Some properties of a substance change, but the substance is still the same  Shredding paper, breaking glass, ice cube melting end

Physical vs. Chemical Changes Chemical Change  When a substance reacts and forms one or more new substances  The composition of the matter changes end

Physical vs. Chemical Changes Evidence of a chemical change:  Change in color Copper roof -> green  Production of a gas See bubbles forming  Formation of a precipitate Forms a solid  Temperature change  Production of light end

States of Matter There are 5 states of matter (phases of matter)  We only care about 3 of them Solid Liquid Gas end

States of Matter- Solids Solid  Something with a fixed shape and a fixed volume  Particles are very close together and vibrate end

States of Matter- Liquid Liquid  Something with no fixed shape but a fixed volume  Particles are free to move around  Also called a fluid end

States of Matter- Gas Gas  Something with no fixed shape and no fixed volume  Particles spread apart to fill the space available end

States of Matter- Other Plasma  Exists at high temperatures and high pressure  Stars Bose-Einstein Condensate (BEC)  Exists near absolute zero at very low pressures  Solid acts as a single particle end

Behavior of Matter Kinetic Theory of Matter  All particles of matter are in constant motion  The state of matter depends on the amount of motion  Originally developed to describe gases Kinetic Energy  The energy an object has due to motion  More Speed = More Kinetic Energy end

Behavior of Matter- Gases Particles move so fast that they are not attracted to each other Particles move in a straight line until they hit something  Act like billiard balls end

Behavior of Matter- Gases Kinetic Theory of Gases  The motion of a gas allows it to fill a container of any shape or size  3 main points Particles in a gas are in constant, random motion The motion of 1 particle is not affected by the motion of other particles, unless the particles hit each other Forces of attraction between particles are ignored end

Behavior of Matter- Liquids Particles move slower than gases Each particle is attracted to the others Fight between a particle’s constant motion and the attraction to the other particles end

Behavior of Matter- Solids Particles are extremely attracted to each other They move very little  Vibrate back and forth in the same spot end

Changes of State (Phase Changes) Phase Change  A reversible physical change  A substance goes from 1 state of matter to another 6 common phase changes  Melting and Freezing  Vaporization and Condensation  Sublimation and Deposition end

Changes of State (Phase Changes) Gas Solid Liquid Sublimation Deposition Melting Freezing Vaporization Condensation end

Changes of State- Energy When you heat something up you give it energy  And the temperature goes up UNTIL it changes to another state!  When something goes through a phase change, the temperature stays the same.  The heat you add is breaking the attraction between particles and pushing them away from each other end

Changes of State- Energy Solid- Temperature is going up Melting- Temperature is staying the same Liquid- Temperature is going up

Changes of State- Energy Temperature is not changing during melting, but heat is added Temperature is not changing during boiling, but heat is added

Changes of State- Energy If you have to add energy, the phase change was endothermic  Melting, Vaporization, Sublimation If you have to take away energy, the phase change was exothermic  Freezing, Condensation, Deposition end

Changes of State- Melting and Freezing Melting  Some molecules in a solid, gain energy to overcome attractive forces to become a liquid Freezing  Some molecules in a liquid, start to slow down and become attracted to each other as a solid end

Changes of State- Vaporization and Condensation Vaporization  Some molecules in a liquid, gain energy to overcome attractive forces to become a gas  Heat of Vaporization The amount of energy needed to move from a liquid to a gas  Evaporation Changing a liquid to a gas at temperatures below the boiling point Spilled water “disappears” after a few hours end

Changes of State- Vaporization and Condensation Condensation  Some molecules in a gas, start to slow down and become attracted to each other as a liquid  The outside of your cold drink, on a hot day end

Changes of State- Sublimation and Deposition Sublimation  Some molecules in a solid, gain energy to overcome attractive forces to go to a gas  Dry Ice (carbon dioxide) Deposition  Some molecules in a gas, start to slow down and become attracted to each other as a solid  Frost on cold windows end