Test 1 Review SheetChapter 1- Chemistry: The science that seeks to understand what matter does by studying what atoms and molecules do- Matter: Anything that occupies space & has mass (EXCEPT in a vacuum)- Properties: Characteristics of matter based on observations and measurements- Matter is classified in 3 ways…1. Solid: molecules are ordered, closely packed, & vibrate - FIXED SHAPE & FIXED VOLUME2. Liquid: Molecules are farther apart and flow past each other - NO FIXED SHAPE BUT FIXED VOLUME3. Gas: Molecules very far apart - NO FIXED VOLUME OR FIXED SHAPE- Heterogeneous Mixture: Not uniform throughout, diff composition, colors, shapes, etc.(sand, a cake)- Homogeneous Mixture (solution): Is uniform throughout and has a variable composition (made up of diff things to become one)**All matter is made of atoms** **Atoms are the building blocks of elements**- Elements: Pure substances that cannot be separated into simpler substances by normal chem. means**Periodic Table is arranged by increasing atomic #**- Dmitri Mendeleev created the PT- Compound: Pure substance composed of 2 or more elements united chemically in a fixed ration- Law of Infinite Proportions: Elemental proportion of a given compound is always the same - Joseph Proust- Physical Properties: Can be observed without changing the composition A. Intensive Properties: Do not depend on quantity (how much matter is present) EX: Color, luster, melting point, densityB. Extensive Properties: Depend on quantitiy (how much matter is present) EX: mass, volume, length- Chemical Properties: Can only be observed by changing the composition of a substance EX: Corrosiveness, flammability,reactvivity - Kilo= k, 10^3- Milli= m, 10^-3- Micro= u, 10^-6- Nano= n, 10^-9- Pico= p, 10^-12- Volume: Length^3 LxWxH L=(dm)^3- Density: M/V (kg/L) OR (g/mL)- Common Scales…1. Celsius- Freezing Point= 0 C / Boiling Point= 100 C **100 difference**2. Fahrenheit- Freezing Point= 32 F / Boiling Point= 212 **108 difference**3. Kelvin- Freezing Point= 273 K / Boiling Point= 373 K **100 difference**K= Celcius temp + 273.15C= 5/9(Fahrenheit - 32)F= (9/5Celcius) +32- Parrallax Effect: You need to make sure you're eye level & parallel to what you're reading- Accuracy: How close a measurement is to the true value (bullseye)- Precision: How close a group of measurements are to each other**Last number in a measurement is uncertain****The greater the precision, the greater the # of sig figs**- Sig fig rules…1. All non zeroes are sig2. Zeroes between non zeroes are sig3. Zeroes to the left of first non zero digit are NOT sig (0.00034 has 2 sig figs)4. Zeroes at the end of the number & to the right of decimal are sig (0.00340 has 3 sig figs)5. Zeroes at the end of a number without a decimal are ambiguous (570) Preferable: 5.7x10^2**When adding/subtracting report answer to the fewest decimal places****When multiplying/dividing report answer to the fewest sig. figs.**Scientific Method: Obsevation— Hypothesis — Experiment — (repeat) — (re do from beginning if wrong) — Theory or Model — LawChapter 2- Law of Conservation of Mass: Mass cannot be created or destroyed & total make of reactant before a run will = the mass of the products- Law of Definite Proportions: All samples of a compound have the same composition (proportions of elements)- Dalton’s Atomic Theory…1. Each element is composed of atoms. Atoms cannot be created or destroyed.2. All atoms of an element are alike in mass & other properties The atoms of one element differ from each other.3. In a compound, diff elements combine in a simple numerical ratioScientists:1. Faraday: Created cathode ray tube to help discover electrons2. JJ Thompson: Observed the glowing of negative particles in cathode ray for every substance (electrons)3. Milikan: Oil-drop experiment - determined charge and mass of electron 4. Rontgen: observed glowing outside of cathode ray & called them x-rays5. Becquerel: discovered radioactivity (spontaneous emission of radiation from certain unstable elements) w/ photograohic plates & uranium-coated coins- Atomic Model (Proposed by Rutherford & Geiger)…1. Most of the mass & al of the + charge or an atom is centered in nucleus, remainder is empty space2. Magnitude of the + charge is diff. for every element3. The # of electrons outside to nucleus =’s the # of protons inside the nucleus (if neutral)4. Nucleus is extremely dense & extremely small #N= Mass number - Atomic number Isotopes: Atoms of an element that have the same Atomic number (protons) but diff mass numbers (neutrons)Ions: Charged atoms created when atoms gain or lose electrons **Atoms that gain electrons= negative charge = anion****Atoms that lose electrons= positive charge = cation**- An atom may have several isotopes, each w their own mass- Isotopic Mass: The mass of 1 atom of an isotope of 1 isotope of an element (must be determined experimentally- Not on PT)- Atomic Mass: Average of all of the isotopic masses of an element, weighted accordingto the abundances of the isotopes (Given on PT)**Atomic mass=Atomic Weight**AW= Sum of [(AM of X isotope)(fractional abundance of X isotope)+(AM of Y isotope)(fractional abundance of Y isotope)]**Periods= Across****Groups=Down****Group 1= Alkali metals**Group 2= Alkali earth metals**Group 6= Chalcogens**Group 7= Halogens**Group 8= Noble Gases**Period 6= Lanthanides (bottom of PT)**Period 7= Actinides (bottom of PT)Properties of Metals:LustrousHigh electrical and thermal conductivitySolids @ room tempMalleable (can be pressed into think sheets)Ductile (Can be drawn into wires)Properties of Nonmetals:Low thermal conductivityLow electrical conductivity (except graphite)Brittle, not malleable or ductile@ room temp: 6 soils (C, P, S, Se, I), 1 liquid (Br), 11 gases**Only noble gases naturally exist as isolated atoms**Molecule: 2 or more atoms bonded tgDiatomic Molecule: 2 atoms of the same element bonded tg (CLIF H BrON)Compound: Composed of molecules w/ more than 1 type of atomMolecular Formula: (Shows composition only) Chemical formula which indicates the actual # of each type of atom w/ a subscriptStructural Formula: (shows composition & connectivity) Structures that show the order inwhich the atoms are bonded**atoms tend to gain or lose electrons to become like the nearest noble gas**Reactivity Trends: Metals tend to form cations, Nonmetals tend to form anions (EXCEPTH+)Polyatomic Ions: Compounds w a chargeNH4+ Ammonium Ion
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