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34 Cards in this Set
- Front
- Back
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Substance
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Matter that has a uniform and unchanging composition. Cannot be broken down by physical means; can be chemically broken down into its component parts. Ex.) table salt, water.
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Physical Property
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Property that can be observed without a change in substance (without altering the identity).
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Extensive Properties
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Depend on the amount of matter present. Ex.) color, state of matter, mass,volume, length.
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Intensive Properties
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Do NOT depend on the amount of matter present-important in identifying unkowns. Ex.) Melting/boiling point, density.
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Chemical property
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Observable only when a substance is undergoing a chemical change. The ability of a substance to combine with or change into one or more other substances. Ex.) Ability to rust, burn, or tarnish.
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States of Matter
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also called phases; explained by the particle theory of matter.
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Solid
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A definite shape and volume; tightly packed particles makes it almost incompressible.
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Liquid
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Definite volume but no shape, it takes the shape of the container, and is a fluid.
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Gas
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No definite shape or volume.
-the term "gas" used if normally gas at room temperature -"vapor" used if normally a liquid or solid at room temperature. Ex.) oxygen gas, water vapor. -takes the shape of and fills their containers and is a FLUID. |
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Plasma
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4th state of matter only found in stars or lightning bolts; exists at temperatures 10^9 power to 10^10 power Celcius (C).
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Physical change
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Occurs if the same substance remains after the change (does not change the identity of the substance). Ex.) Verbs such as crush, split,grind, crumple indicate this type of change.
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Chemical change
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Occurs if a new substance is present after the change- difficult if not impossible to reverse. Ex.) Fermentation of juices,iron with rust on it after exposed to air, verbs such as explode, rust, oxidize, corrode, tarnish, ferment, burn, or rot generally refers to this change in which reactant substances produce different product substances.
-RULE OF THUMB:If a precipitate is formed, a gas is given off (bubbles), color change, or there is an energy change (heat or light), then this change has occured. -Precipitate-a solid produced during a chemical reaction in a solution. |
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Law of Conservation of Mass
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The total amount of matter in the universe remains constant; matter is neither created nor destroyed in ordinary chemical reactions. Mass reactants=Mass products
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Mixture
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A combination of two or more pure substances in which each pure substance retains its individual chemical properties and can be separated physically through physical changes not chemical changes. The substances can be mixed in any ratio.
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Heterogeneous mixtures
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A mixture that does not blend smoothly throughout and in which the individual substances remain distinct; has different phases. Ex.) Colloids and suspensions.
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Colloids
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Heterogeneous mixtures containing particles larger than a solution's particles, but smaller than suspension particles. (The mixture appears opaque, but the particles don't settle out.) Ex.) blood, butter, milk, whipped cream, smoke, clouds, jello, mousse.
-Exhibits the Tyndall effect. |
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Suspensions
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Heterogeneous mixtures whose particles settle out over time and whose particles can be removed by filtration, settling, or centrifuging. Ex.) muddy water, oil and water, blood, liquid medications.
-Exhibits the Tyndall effect |
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Homogeneous mixture
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Has a uniform compostion throughout and looks like a pure substance; it always has a single phase (looks the same throughout). Ex.) Solutions= solute and solvent.
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Solution
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A type of homogeneous mixture; concentration of solutes in solvents and commonly measured in molarity (M).
-Solute- dissolved material -Solvent- dissolving material such as sugar in iced tea. -In general, the majority substance is the solvent, the minority substance is the solute (oxygen (21%) in nitrogen (78%) which is air. -Five types of solutions: 1. Solid/ liquid-Ex: Salt and water- can be separated by evaporation or distillation 2. Liquid/liquid-Ex:alcohol and water- can be separated by distillation ( boiling point differences). 3. Gas/liquid-Ex: Carbonated soda- can be separated by agitation, heating, reduced pressure. 4. Gas/ gas- Ex: Air ( mainly oxygen dissolved in nitrogen)- can be separated by gas chromatography. 5. Solid/solid-Ex: 10 carat gold or sterling silver- can be separated by melting poing differences. |
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Filtration
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A technique that uses a porous barrier to separate a solid from a liquid.
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Distillation
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A separation technique used to separate substances based on different boiling points.
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Crystallization
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A separation technique that results in the formation of pure solid particles from a solution containing the dissolved substance.
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Chromatography
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A technique that separates the components of a mixture on the basis of the tendency to travel across another material.
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Elements
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Cannot be broken down into simpler substances; composed of one kind of atom; list on the periodic table of the elements.
-Elements are arranged on the periodic table which was first produced by Dmitri Mendeleev in 1869. |
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Compounds
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A combination of two or more different elements that are combined chemically.
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Law of definite composition
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A law that states regardless of the amount, a compound is always composed of the same elements in the same proportion by mass.
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Law of multiple proportions
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Different compounds can be composed of the same elements in different ratios.
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Energy
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The ability to cause change.
-measured in Joules. -many forms: radiant, electrical, thermal, nuclear -kinetic:energy in the form of motion; depends on mass and velocity -potential: stored energy; depends on position or condition -the total amount of kinetic and potential energy in a system is the mechanical energy. |
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The law of conservation of energy
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States that energy may change form but it cannot be created or destroyed under ordinary conditions.
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Temperature
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Measure of the average kinetic energy of the particles in a sample of matter; as movement (KE) increases due to an increase in heat energy, temperature increases
-measured in Kelvin (SI unit) (K=C+273) 0 K= absolute zero 273 K= freezing point of water 373 K= boiling point of water -in lab, measured in Celcius with a thermometer |
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Thermal energy
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Total energy of the particles in a material, including both kinetic and potential energy (kinetic energy due to the vibration and movement within and between particles; potential energy is determind by forces that act within or between the particles).
-increases mass (at the same temperature) |
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Heat
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The thermal energy that flows from something with a higher temperature to something with a lower temperature; energy transferred between objects due to a temperature difference; measure in Joules.
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Exothermic
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Reaction that releases energy; feels hot; generally spontaneos.
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Endothermic
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Reaction that absorbs energy; feels cold; rarely spontaneous.
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