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66 Cards in this Set
- Front
- Back
Difference between an observation and inference?
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an observation is what is seen while an inference is an assumption made on top of that observation
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Units used to measure mass?
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grams
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Units used to measure volume?
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cubic centimeters or Liters
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What is density?
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(mass/volume) - represents the amount of the substance compacted into a certain volume of that substance
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All _____ numbers are significant.
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nonzero (Ex. 3.4grams has two sig figs)
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Zeros lying between nonzero numbers are ________
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significant (Ex. 3.04grams has two sig figs)
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Zeros to the left of all the nonzero digits are ________
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not significant (Ex. 0.0034grams has two sig figs)
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Zeros to the right of all the nonzero digits are _______ if there's a _______ written in the number
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1) significant
2) decimal point 3) Ex. 1000 has one sig fig, whereas .1000 has four sig figs |
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Numbers in scientific notation have the _______ of sig figs as ______ part of the number _______
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1) same number
2) the decimal 3) before x10 4) Ex. 4.30 x 10^5 has three sig figs |
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Sig Figs: Addition and Subtraction
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answer has same number of sig figs to the right of the decimal as the added number with the fewest does (Ex. 3.4 + 5.02301 = 8.42301 ~ round to 8.4 b/c 3.4 has one sig fig to the right of the decimal)
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Sig Figs: Multiplying & Dividing
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answer should have the same number of sig figs as the original number with the fewest (Ex. 1.22 x 3.487 = 4.25414 ~ round to 4.25 b/c 1.22 has only three sig figs)
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What properties can be used to identify substances?
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density, melting/boiling point, solubility, physical properties
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What properties cannot be used to identify substances?
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mass and volume
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States of Matter: Solid
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definite shape and volume
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States of Matter: Liquid
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flows, has a fixed volume, takes the shape of its container
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States of Matter: Gas
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takes both the shape and volume of its container and is easily compressed
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Difference between and pure substance and a mixture?
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a pure substance is uniformly made up of the same element while a mixture is a physical blend of different substances
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Homogenous vs. Heterogenous
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1) Homo - completely uniform composition; components evenly distributed throughout the sample
2) Hetero - not uniform in composition; contents not spread evenly throughout sample |
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What are the measurable properties of gas?
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volume, temperature, pressure, mass, moles
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Assumption #1 of Kinetic Theory:
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there are a lot of individual molecules however those molecules are spread out widely
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Assumption #2 of Kinetic Theory:
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molecules move in random directions at a constant speed
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Assumption #3 of Kinetic Theory:
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molecules only exert force when they collide elastically with their container or other molecules
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Assumption #4 of Kinetic Theory:
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molecules obey Newton's laws of motion
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What is the Ideal Gas Law?
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(P1 x V1) / T1 = (P2 x V2) / T2
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Difference between an element and a compound?
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an element is made up of only one type of atom and has unique properties while a compound is made up of different types of atoms with and has its own unique properties
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How does a compound of two elements differ from a homogenous mixture of the two elements?
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the compound has properties unique of its components and can only be separated by a chemical reaction; the homogenous mixture takes on the properties of its components and can be separated by using those properties
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What is an ion?
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an atom or group of atoms that is +/- in charge
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How to write the chemical formulas for ionic compounds?
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have enough of each element so that the charges will cancel out and be zero
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Scientific Law
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a general statement about the way the world has been observed to work (eg. what goes up must come down)
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Scientific Theory
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an explanation that successfully accounts for scientific observations
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Law of Constant Proportions
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in samples of any chemical compound, the masses of the elements are always in the same proportions
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Law of Multiple Proportions
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elements combine to form compounds in ratios of small whole numbers
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Tenet #1 of Dalton's Atomic Theory:
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all elements are composed of tiny indivisible particles called atoms
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Tenet #2 of Dalton's Atomic Theory:
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atoms of the same element are identical and they are unique from those of another element
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Tenet #3 of Dalton's Atomic Theory:
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atoms can physically mix or chemically combine in small whole number ratios to form compounds
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Tenet #4 of Dalton's Atomic Theory:
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chemical reactions occur when atoms are separated, joined, or rearranged. atoms never change into those of another element though
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How did Dalton come to his conclusions in atomic theory?
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he studied the ratios in which elements combine in chemical reactions
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J.J. Thomsen
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created the Cathode Ray Tube which showed electrons to be negatively charged
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Ernst Rutherford
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created the "alpha particle shooter" which showed that there was something of considerable mass sitting in the center of the electron "cloud"
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What was the major change in Dalton's atomic theory?
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that atoms are divisible into smaller sub-atomic particles
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Protons
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the positively charged sub-atomic particles in the nucleus
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Neutrons
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the other non-charged sub-atomic particle in the nucleus
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Electrons (e-)
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the negatively charged sub-atomic particles that orbit the nucleus
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Nucleus
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the positively charged core of the atom made up of protons and neutrons
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Atomic Number vs. Atomic Mass
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1) Number - number of protons
2) Mass - protons + neutrons |
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Chemical Formula vs. Formula Units vs. Molecular Formulas
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1) Chemical - kinds and numbers of atoms in the smallest unit of the substance
2) Form Unit - used with ionic compounds; lowest whole-number ratio of ions 3) Molecular - kinds and numbers of atoms present in a molecule of a compound |
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Where are metals and non-metals located on the periodic table?
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1) Metals - left of squiggly line
2) Non-metals - right of squiggly line |
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How to differentiate molecular and ionic compounds?
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molecular are made of all non-metals while ionic are made of metals and non-metals
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Greek Prefixes: 1
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mono
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Greek Prefixes: 2
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di
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Greek Prefixes: 3
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tri
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Greek Prefixes: 4
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tetra
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Greek Prefixes: 5
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penta
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Greek Prefixes: 6
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hexa
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Greek Prefixes: 7
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hepta
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Greek Prefixes: 8
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octa
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Why balance equations?
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because we need to make sure that the masses match up because of the law of conservation of mass
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What is a mole?
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6.02 x 10^23; unit of measure like "a dozen"
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How are atomic mass and molar mass related?
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they are equivalent
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Why aren't atomic masses whole numbers?
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because it is the average of the mass of all the elements isotopes
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How is the percent composition of a compound related to the law of Constant proportions?
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in any compound, one of the elements will always make up a certain percentage of the compound
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How do you calculate the molecular mass of a compound?
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add together the atomic masses of all the elements
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Hydrated Crystal
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a crystal that can hold a significant amount of water
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Empirical Formula vs. Molecular Formula
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1) Empirical - lowest ratio of one to the other
2) Molecular - ratio in the compound |
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Limiting Reagent
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the reactant that will run out first
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How to determine the limiting reagent?
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the reactant you have the least of
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