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Ch.1: Matter and Change. 1.1 Chemistry. Sciences. used to be divided into strict categories physical (nonliving) biological (living) Chemistry has parts that fall under both categories many sciences are so interrelated that you can’t categorize them in those ways anymore. Chemistry.
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Ch.1: Matter and Change 1.1 Chemistry
Sciences • used to be divided into strict categories • physical (nonliving) • biological (living) • Chemistry has parts that fall under both categories • many sciences are so interrelated that you can’t categorize them in those ways anymore.
Chemistry • study of matter and the changes it undergoes • chemists use instruments to improve their ability to observe and make measurements
Chemistry • chemists work with chemicals (any substance with definite composition) • all matter has chemical basis whether it is living or nonliving
Branches of Chemistry • organic- study of compounds containing carbon • inorganic- study of compounds that aren’t organic 3. physical- study of changes of matter and their energy
Branches of Chemistry • analytical- study of composition of materials • biochemistry- study of substances and processes in living things • theoretical- use of math and computers to understand chemical behaviors and design new compounds
Types of Research • Basic Research - done to increase knowledge • Applied Research - done to solve a problem • Technological Development - done to improve quality of life • technology – application of knowledge (usually scientific) for practical purposes
Ch.1: Matter and Change 1.2 Matter and Its Properties
Terms • Matter- anything that has mass and volume • Atom- smallest unit of an element that keeps the properties of element • Element- pure substance made of only one type of atom • Compound- substance made of 2 or more types of atoms that are chemically bonded • Molecule- type of compound in which bonds are covalent bonds
Extensive vs. Intensive • Extensive Property • depends on the amount of matter present • Intensive Property • depends on the identity of substance, not the amount
Extensive vs. Intensive • Examples: • boiling point • volume • mass • density • conductivity
Physical vs. Chemical • Physical Property • can be observed without changing the identity of the substance • Chemical Property • describes the ability of a substance to undergo changes in identity
Physical vs. Chemical • Examples: • melting point • flammable • density • magnetic • tarnishes in air
Physical vs. Chemical • Physical Change • changes the form of a substance without changing its identity • properties remain the same • Chemical Change • changes the identity of a substance • products have different properties
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
Physical vs. Chemical • Examples: • rusting iron • dissolving in water • burning a log • melting ice • grinding spices
Kinetic Molecular Theory • KMT • Particles of matter are always in motion. • The kinetic energy (speed) of these particles increases as temperature increases.
Four States of Matter • Solids • very low KE - particles vibrate but can’t move around • fixed shape • fixed volume
Four States of Matter • Liquids • low KE - particles can move around but are still close together • variable shape • fixed volume
Four States of Matter • Gases • high KE - particles can separate and move throughout container • variable shape • variable volume
Four States of Matter • Plasma • very high KE - particles collide with enough energy to break into charged particles (+/-) • gas-like, variableshape & volume • stars, fluorescentlight bulbs, CRTs
MIXTURE PURESUBSTANCE yes no yes no Is the composition uniform? Can it be chemically decomposed? Colloids Suspensions Matter Flowchart MATTER yes no Can it be physically separated? HomogeneousMixture (solution) HeterogeneousMixture Compound Element
Matter Flowchart • Examples: • graphite • pepper • sugar (sucrose) • paint • soda
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 Homogeneous
Tyndall Effect Mixtures • Solution • homogeneous • very small particles • no Tyndall effect • particles don’t settle • EX: rubbing alcohol
Mixtures • Colloid • heterogeneous • medium-sized particles • Tyndall effect • particles don’t settle • EX: milk
Mixtures Main constituents of MilkWater 87.0 (%) Total solids 13.0 (%) Fat 4.0 (%) Proteins 3.4 (%) Lactose 4.8 (%) Minerals 0.8 (%)
Mixtures • Suspension • heterogeneous • large particles • Tyndall effect • particles settle • EX: fresh-squeezed lemonade
Mixtures • Examples: • mayonnaise • muddy water • fog • saltwater • Italian salad dressing
Ch.1: Matter and Change 1.3 Elements
Elements • elements are pure substances • organized by properties on periodic table • each square shows the name and letter symbol for each element • usually the symbols relate to the English names but some come from older names (usually Latin) • Ex: gold’s symbol is Au from aurum • Ex: iron’s symbol is Fe from ferrum
Periodic Table • Groups • also called families • vertical columns • numbered 118 • have similar chemical properties • Periods • horizontal rows • properties changes consistently across a period
Periodic Table • two rows below the periodic table are the lanthanide and actinide series • these rows fit after #57 and #89 • they are only at the bottom to keep the width of the chart smaller
Types of Elements • Metals • an element that is a good conductor of electricity • at room temperature, most are solids • malleable- can be rolled or hammered into sheets • ductile- can be made into wire • high tensile strength- can resist breakage when pulled • most have silvery or grayish white luster
Types of Elements • Nonmetals • an element that is a poor conductor of heat and electricity • many are gases at room temperature • some are solids: usually brittle, not malleable
Types of Elements • Metalloids • an element that has some characteristics of metals and nonmetals • appear along staricase line • B, Si, Ge, As, Sb, Te • all are solids at room temperature • less malleable that metals but less brittle than nonmetals • are semiconductors
Types of Elements • Noble Gases • generally unreactive gases • in far right column of periodic table