MATTER Chapter 2
What s da matter? Matter anything that takes up space and has mass
Classification of Matter (p. 22 table 21-A) Physical Properties physical relationships between particles in the matter Density how densely packed particles are Malleability how easily something can be hammered into a specific shape Ductility stretchiness Conductivity ability to transfer heat
Physical Properties Color Shape Texture Odor Taste Electrical conductivity Density
Chemical Properties Chemical Properties changes in matter due to reaction with other materials Chemical changes = new substances formed
Chemical changes.reactions!
Physical vs. Chemical Signs of a Physical Change Phase Solid liquid, liquid gas, etc. Identity of substance not changed
Physical vs. Chemical Signs of a Chemical Change change in color or odor formation of a gas formation of a precipitate (solid) change in light or heat
B. Physical vs. Chemical Examples: rusting iron dissolving in water burning a log melting ice grinding spices chemical physical chemical physical physical
The Division of Matter (p. 24 Fig. 2A-1) MATTER yes Can it be physically separated? no MIXTURE PURE SUBSTANCE yes Is the composition uniform? no yes Can it be chemically decomposed? no Homogeneous Mixture (solution) Heterogeneous Mixture Compound Element Colloids C. Johannesson Suspensions
Matter Flowchart Examples: graphite pepper sugar (sucrose) salad dressing soda element hetero. mixture compound hetero. mixture solution
Pure Substances Element composed of identical atoms EX: copper wire, aluminum foil
Pure Substances Compound composed of 2 or more elements in a fixed ratio properties differ from those of individual elements EX: table salt (NaCl)
Pure Substances Law of Definite Composition A given compound always contains the same, fixed ratio of elements. Law of Multiple Proportions Elements can combine in different ratios to form different compounds.
Pure Substances For example Two different compounds, each has a definite composition.
Mixtures Variable combination of 2 or more pure substances. Heterogeneous- Quartz, mica, feldspar in granite Homogeneousapple cider
Mixtures Solution Homogeneous mixture very small particles Tyndall Effect no Tyndall effect (light scatter) particles don t settle EX: rubbing alcohol
Mixtures Colloid heterogeneous medium-sized particles Tyndall effect particles don t settle EX: milk
Mixtures Suspension heterogeneous large particles Tyndall effect particles settle EX: fresh-squeezed lemonade
Mixtures Examples: mayonnaise muddy water fog saltwater Italian salad dressing colloid suspension colloid solution suspension
Mixture vs. Compound
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Elements of the Periodic Table An element is a pure substance that can t be broken down into a simpler substance by ordinary chemical means.
Atoms particles in elements
Diatomic vs. Polyatomic
Molecule smallest unit of a compound C 8 H 10 N 4 O 2
Energy in Matter Chemical reactions energy is released or absorbed Exothermic release Endothermic absorb Different types of energy: Chemical Thermal Electric Nuclear
Thermodynamics the flow of energy
Thermodynamics 1 st Law mass/energy can be neither created or destroyed, it is conserved Energy changes forms 2 nd Law the amount of usable energy in a closed system will decrease over time Entropy is the randomness or disorder in a system Things always seem to head in the direction of disorder The universe is dying
Energy of Motion Kinetic energy Thermal energy Heat
Temperature
Phases (States) of matter Four Phases of Matter: Solid Liquid Gas Plasma
Solids very low KE - particles vibrate but can t move around fixed shape fixed volume
Liquids low KE - particles can move around but are still close together variable shape fixed volume
Gases high KE - particles can separate and move in container variable shape variable volume
Plasma very high KE - particles collide with enough energy to break into charged particles (+/-) gas-like, variable shape & volume stars, fluorescent light bulbs, lightning