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77 Cards in this Set
- Front
- Back
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Matter
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Has Mass and occupies space
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What are the "building blocks" of all matter?
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Atoms
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Property
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any characteristic that allows us to recognize a particular type of matter and to distinguish it from other types
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Elements
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The most basic substances (100 elements compose all matter)
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Molecules
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(aka compound) combinations of atoms (composition) held in specific shapes (structure)
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Chemistry
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Study of properties of materials and changes they undergo
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Why is chemistry the Central Science?
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Because it is so vital to a fundamental understanding of other sciences and technologies
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Composition
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element, compound, or mixture
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State
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solid, liquid, or gas
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Properties of Gas
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-No Fixed Volume
-Compressible |
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Ways of classifying matter:
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Physical (gas, liquid, or solid) and Composition (element, compound, or mixture)
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States of matter
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Physical states (gas, liquid, or solid)
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liquid
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-No fixed shape
-Volume is independent of container -Not compressible On molecular level... fewer collisions; molecules "slide" over each other |
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Solid
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-Rigid 3-D structure
-Not compressible On molecular level... -defined 3-D orientation |
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Pure substance
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fixed compositions; distinct properties
can't decompose into smaller subunits e.g. elements, water |
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Elements v. Compounds
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Elements: Cannot be decomposed into simpler substances
Compounds: contain two or more kinds of atoms |
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Mixture
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combination of 2 or more pure substances and each substance retains its individual properties
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How many known elements?
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117
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How are elements organized?
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on periodic table. each has unique name and symbol
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Law of constant composition (Law of Definite Proportions)
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developed by Louis Proust
-the elemental composition of apure compound is always the same (chlorine from a lab is the same as chlorine from nature) |
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Law of Constant Proportions
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A compound always consists of the same combination of elements
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Mixture
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Combination of two or more pure substances (each substance retains its identity)
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Heterogeneous Mixture
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Mixtures that do not have the same composition, properties, and appearance throughout (a salad, oil and water)
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Components of a Mixture
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Substances making up the mixture
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Homogeneous Mixture
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Mixtures that are uniform throughout (sugar water, asprin)
Also Called Solutions |
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The two properties of matter
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Physical and Chemical
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Physical Properties
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can be observed without changing the identity and composition of the substance (color, density, odor, boiling point, hardness, all changes of state-gas, liquid, solid)
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Chemical Properties
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describes the way a substance may change or react to form other substances (flammability)
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Intensive Properties
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Independent of amount of substance (1 teaspoon of water and a gallon of water both boil at 100C)
These are used to identify the substance |
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Extensive properites
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depend on quantity of substance and are used to relate to the amount of substance present
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Physical Change
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substance changes appearance, but not its composition (all changes of state, water to vapor- still H2O)
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Chemical Change
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(aka chemical reaction) substance is transformed into a chemically different substance
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Filtration
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remove solid from liquid
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Distillation
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boil off one or more componenets of the mixture
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Separation of Mixtures
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separation techniques exploit differences in properties of the components
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Chromatography
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-differening abilities of substances to adhere to the surfaces of varoiius solids) (exploit solubility of components)
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Scientific Method
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Collect data (observation)--> hypothesis (patterns seen)--> test (well controlled extensive experimentation--> law --> theory
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hypothesis
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tentative explanation based on seen patterns that guids in planning further experiments
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Scientific law
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Conscise verbal statement or mathematical equation that summarizes a broad variety of observations and experiences
aka. Description of observed phenomenon, just described |
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Theory
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an explanation of gerneral causes of certain phenomena with considerable evidence or facts to support it.
aka. Explanation, why scientific laws are true |
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SI units
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Système International d’Unités
Standard units (kilogram (kg), meter (m), second (s^a), kelvin (K), mole (mol), ampere (A), candela(cd)) |
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Giga
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G (10^9)
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Mega
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M (10^6)
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Kilo
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k (10^3)
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Deci
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d (10^-1)
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Centi
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c (10^-2)
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Milli
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m (10^-3)
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Micro
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μ^a (10^-6)
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Nano
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n (10^-9)
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Pico
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p (10^-12)
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Femto
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f (10^-15)
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Mass
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measure of amount of material in an object
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Temperature
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measure of the hotness or coldness of an object
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How many degrees C are in each degree of Farenheit?
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1.8C=1F
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How many degree intervals are between boiling and Freezing in Farenheit?
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180 intervals (32 to 212)
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What is absolute zero in celcius?
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-273.15
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Formula for converting farenheit to C?
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C=(5/9)(F-32)
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Formula for converting Celcius to Farenheit:
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F=(9/5)(C) +32
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Formula for converting Celcius to Kelvin
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K=C+273.15
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Derived SI units
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formed from the seven base units (e.g. velocity [m/s] volume [m^3] and density [m/v])
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Exact numbers
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numbers whose values are known exactly e.g. 1000g in a Kilogram, counting people in a classroom
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Inexact numbers
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numbers whose values have some uncertainty e.g. measurement
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Precision
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measure of how closely individual measurements agre with one another
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accuracy
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how closely individual agreements agree qith the correct, or "true" value
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Standard Deviation
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hw much the individual measurements differ from the average (measures precision)
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What are the digits of a measured quanitty called?
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All digist of a measures quantity, including the uncertain one, are called significant figures
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How many significant figures does the following number have? 2.2405
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5
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Rules for determining number of significant figures with zeroes
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1. Zeros between nonzero digits are always significant
2. Zeroes at the beginning of a number are never significant 3. Zeroes at the end of a number are significant if the number cantains a decimal point |
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how many uncertain digits should an answer have
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1
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How do you determine sig figs in addition and subtraction?
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look at the number with the fewest decimal places
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how do you determine the number of sig figs in mult/division
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look at number with the least amount of sig figs
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For exact numbers, do sig figs need to be calculated at the end?
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No, use exact numbers as if they had an infinite number of sig figs
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Rules for rounding off numbers
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Look at leftmost digit to be removed: less than 5 round down, 5 or greater round up
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dimensional analysis
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carry units through all calculations> units are divided into eachother, multiplied together or canceled
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What is the key to using dimensional analysis?
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Conversion factors (changing one unit into antoher)
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Conversion factor
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simple ratios used to convert one unit to another
desired unit/ given unit numerator and denominator are same quantity expressed in different units |
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What are the 3 questions asked in dimensional analysis?
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1. What data are we given?
2. What quantity do we need? 3. What conversion factors are available to take us from what we are given to waht we need? |
