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50 Cards in this Set
- Front
- Back
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Chemistry
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Study of materials and the changes that materials undergo
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Matter
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anything that has mass and occupies space
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Elements
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Book: very basic, or elementary
Dictionary: irreducible constituent of a composite entity |
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Atoms
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Book: infinitesimally small building blocks of matter
Dictionary: a part or particle considered to be an irreducible constituent of a specified system |
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Molecules
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Book: two or more joined atoms
Dictionary: The smallest particle of a substance that retains the chemical and physical properties of the substance and is composed of two or more atom |
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Submicroscopic
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Book: atoms and molecules
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Macroscopic
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Book: ordinary sized objects
Mine: objects that can be seen with the unaided eye |
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Why study?
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It is the central science, fundamental to other sciences
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States of Matter
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gas, solid, liquid
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Gas
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aka Vapor
no fixed volume or shape, conforms to volume and shape of its container |
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Liquid
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Volume is independent of container, shape is dependent on container
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Solid
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Definite volume, definite shape
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Molecular Properties of States of Matters
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Gas: molecules far apart, moving quickly
Liquid: molecules close together, moving quickly Solid: molecules held tightly together, can wiggle only slightly in fixed positions |
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Pure Substance
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matter that has distinct properties and a composition that does not vary from sample to sample.
Elements or compounds. |
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Compounds
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substances composed of two or more elements
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Mixtures
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Combinations of 2 or more substances in which each substance retains its own chemical identity
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Diatomic Molecules
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those consisting of two atoms
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Law of Constant Composition
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aka Law of Definite Proportions
Observation that the elemental composition of a pure compound is constant, regardless of its source |
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Mixture Component
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constituent substances of a mixture
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Heterogeneous Mixture
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varies in texture and appearance
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Homogeneous Mixture
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uniform throughout
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Solutions
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homogeneous mixture, any state of matter
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Physical Properties
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observable without changing identity and composition of substance
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Chemical properties
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describe the way a substance may react to form other substances
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Intensive properties
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Those that do not depend on the amount of the sample, e.g. temperature, melting point, density
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Extensive properties
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those that relate to the amount of the substance present, e.g. volume, mass
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Physical change
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change in appearance, not composition; e.g. water evaporation
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Changes of State
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all are physical changes
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Chemical Change
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aka chemical reaction
transformation into a chemically different substance |
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Filtration
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Separation of liquid and solid by forcing the mixture through a porous medium
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Distillation
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Method of separating components that depends on differing abilities of substances to form gases
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Chromatography
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Separation of mixtures dependent upon the differing abilities of substances to adhere to the surface of various solids.
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Scientific method
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Observation & experiments > find patterns, trends & laws > formulate & test hypothesis > theory
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Hypothesis
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tentative explanation
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Scientific law
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concise verbal statement or mathematical equation that summarizes a broad variety of observations & experiences
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Theory
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Explanation of the general causes of a certain phenomena with considerable supporting facts and evidence
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SI Units
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1960 international agreement specifying base units to be used in scientific measurement
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Meter
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SI base unit of length
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Mass
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SI base unit of kilogram
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Kelvin
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SI base unit of temperature, Celsius scale often used
K=C+273.15 |
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Derived SI Units
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Speed: ratio of length traveled to elapsed time
Volume: length cubed |
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Density
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mass/volume
mass in grams, volume in cubic cm or mL |
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Precision
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a measure of how closely individual measurements agree
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Accuracy
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how closely individual measurements agree with the correct value
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Standard Deviation
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shows the extent to which individual measurements differ from the average
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Significant Figures
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all digits of a measured quantity except leading zeros or trailing zeros in a number without a decimal
1005=4 sf, 100=1 sf, 0.02=1 sf, 0.0200=3 sf To indicate significance in a number with trailing zeros and no decimal, use exponential notation 10300=3sf, 1.03*10^4=3sf, 1.030*10^4=4sf, 1.0300*10^4=5sf |
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Uncertain Digits
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generally only the last, or most precise, digit of a measurement
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Significant Figures in Calculations
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The least certain measurement limits the certainty of the calculated quantity and thereby determines the number of significant figures in the final answer
Multiplication & Division: round the result to have the same number of significant figures as the measure with the fewest significant figures 6.221*5.2=32.3492, round to 32 Addition & Subtraction: round the result to the same number of decimal places as the number with the least decimal places 83.1+20.42+1.322=104.842, report as 104.8 |
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Conversion Factors, English to Metric
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1 mile=1.6903 km
1 foot = 30.48 cm or 0.3048 m 1 inch = 2.54 cm 1 gallon = 3.7854 L 1 pound = 453.59 g 1 ounce = 28.3494 g 1 inch ^3 = 16.3871 cm ^3 5C per 9F, adjust for 32 |
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Density formula
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Density = mass / volume
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