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103 Cards in this Set
- Front
- Back
Matter
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anything that has mass and occupies space
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energy
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the capacity to do work or to transfer heat
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kinetic energy
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represents the capactiy for doing work directly
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potential energy
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energy an object possesses because of its position
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Law of Conservation of Matter
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there is no observable change in the quantity of matter during a chemical reaction or during a physical change
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Law of Conservation of Energy
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energy cannot be created or destroyed in a chemical reaction or in a physical change. It can only be converted from one form to another
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Law of Conservation of Matter and Energy
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The combined amount of matter and energy available in the universe is fixed
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Daltons Atomic Theory
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1. An element is composed of extremely small, indivisible particles called atoms
2. All atoms of a given element have identical properties that differ from those of other elements 3. Atoms cannot be created, destroyed, or transformed into atoms of another element in chemical or physical changes 4. Compounds are formed when atoms of different elements combine with one another in small whole-number ratios 5. The relative numbers and kinds of atoms are constant in a given compound |
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atoms
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the smallest particle of an element that maintains its chemical identity through all chemical and physical changes
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molecules
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smallest particle of an element or compound that can have a stabe independent existence
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Which elements exist in nature as diatomic molecules?
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Hydrogen, nitrogen, fluorine, chlorine, bromine, and iodine
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Chemical properties
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undergoes change in composition
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physical properties
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absence of any change in composition
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Mixtures
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combination of two or more substances in which each substances retains its own composition and properties
variable composition, components retain their characteristic properties, may be separated into pure substances by physical methods |
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pure substances
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fixed composition, cannot be separated into simpler substances by physical methods, can only be changed in identity properties by chemical methods, under identical conditions, properties do not vary
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homogeneous
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(solution) kind of mixture that has uniform properties throughout
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heterogeneous
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mixture in which different portions of the sample have recognizably different properties
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compounds
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substance that can be decomposed by chemical means into simpler substances
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element
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substance that cannot be decomposed into simpler substances by chemical changes
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Law of Definite Proportions( Law of Constant Composition)
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different samples of any pure compound contain the same elements in the same proportions by mass
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length
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meter
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mass
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kg
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time
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s
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temp
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K
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mass
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measure of quantity of matter a body contains
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weight
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measure of the gravitational attraction of the earth for the body
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Most common temperatures
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C, F, K
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Solids
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have molecules that are packed together tightly
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Liquids
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made of molecules that are close but can still move around
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gases
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made up of free-moving molecules
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Fluids are:
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liquids and gases because they flow freely
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Solids and liquids are referred to:
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condensed states because they have much higher densities then gases
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miscible
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they mix completely unless they mix with one another
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pressure
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force per unit area
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barometer
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measures atmospheric pressure
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manometer
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measures the pressure of a gas
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What are the two main gases in clean, dry, air? What are their approximate %'s?
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N_2 - 78%, 0_2 - 20.94%, Ar - .93%
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What is the typical pressure of the atmosphere in our classroom in pounds per square inch? atmospheres? torr? mm of mercury? inches of mercury?
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14.69 PSi
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What is the greenhouse effect?
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CO_2 and H_2O absorb the heat from the earth and keep it trapped in the atmosphere, warming the earth
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What are the primary greenhouse gases?
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CO_2 and H_2O
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What is the relationship between the greenhouse effect and global warming?
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because the energy from the earth is trapped, the world warms up and then it disturbs the ecosystems
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What are some possible problems from global warming?
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ice melting planting seasons, rain cycles
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Boyles Law
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For a gas at a constant temp, the volume and pressure is always the same number
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Charles' Law
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at a constant temperature, the volume occupied by a definite mass of a gas is directly proportional to its absolute temperature
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Atomic number
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the number of protons in the nucleus of an atom
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Heat
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a form of energy that flows between two samples of matter because of their difference in temperature
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Law of Definite Proportions (Law of Constant Composition)
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Different samples any pure compound contain the same elements in the same proportions by mass
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Mixture
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A sample of matter composed variable amounts of two or more substances, each of which retains its identity and properties
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Properties
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characteristics that describe samples of matter
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Specific gravity
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the ratio of the density of a substance to the density of water at the same temp
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Substance
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any kind of matter all specimens of which have the same chemical composition and physical properties
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Allotropes
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different forms of the same element in the same physical state
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Anhydrous
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without water
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Anion
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An ion with a negative charge
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Atomic mass unit (amu)
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One twelfth of the mass of an atom of the carbon-12 isotope; a unit used for starting atomic and formula weights
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Cation
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A ion with a positive charge
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Chemical formula
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Combination of element symbols that indicates the chemical composition of a substance
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Composition stoichiometry
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describes the quantitative relationships among elements in compounds
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Formula
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Combination of element symbols that indicates the chemical composition of a substance
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Formula unit
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the smallest repeating unit of a substance-for non-ionic substances, the molecule
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Hydrate
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A crystalline sampe that contains water, H20, and another compound in a fixed mole ratio
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Ion
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An atom or group of atoms that carries an electric charge
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Ionic compound
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A compound that is composed of cations and anions
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Law of Definite Proportions
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Different samples of a pure compound always contain the same elements in the same proportions by mass
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Law of multiple proportions
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when two elements form more than a compound,
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Molar mass
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the mass, in grams, of one mole of a substance; numerically equal to the formula weight of the substance
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Mole
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(Avogradro's number) formula units molecules of a substance. The mass, in grams, of one mole is numerically equal to the formula weight of the substance
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Molecular formula
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A formula that indicates the actual number of atoms present in a molecule of a molecular substance
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Molecular weight
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the mass, in amu, of one molecule of a non-ionic (molecular) substance
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Percent composition
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The mass percentage of each element in a compound
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Percent purity
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The mass percentage of a specified compound or element in an impure sample
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Polyatomic
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Consisting of more than one atom
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Simplest formula
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the smallest whole-number ratio of atoms present ina compound
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Stoichiometry
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description of the quantitative relationships among elements in compounds (composition stoichiometry) and among substances as they undergo chemical changes
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Structural formula
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A representation that shows how atoms are connected in a compound
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Absolute zero
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The zero point on the absolute temperature scale
-273.15C or O K |
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Atmosphere (atm)
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A unit of pressure
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Avogadro's Law
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At the same temperature and pressure equal volumes of all gases contain the same number of molecules
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Bar
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A unit of pressure
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Barometer
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A device for measuring atmospheric pressure
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Boyle's Law
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At constant temp, the volume occupied by a given mass of a gas is inversely proportional to the applied pressure
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Charles' Law
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At constant pressure, the volume occupied a definite mass of a gas is directly proportional to its absolute temp
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Condensed states
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The solid and liquid states
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Dalton's Law of Partial Pressures
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The total pressure exerted by a mixture of gases is the sum of the partial pressures of the individual gases
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Diffusion
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The movement of a substance into a space or the mixing of one substance with another
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Dispersion forces
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Weak, short-range attractive forces between short-lived temporary dipoles
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Effusion
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The escape of a gas through a tiny hole or a thin porous wall
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Fluids
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Substances that flow freely; gases and liquids
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Gay-Lussac's Law of Combining Volumes
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At constant temperature and pressure, the volumes of reacting gases (and any gaseous products) can be expressed as ratios of small whole numbers
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Ideal gas
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A hypothetical gas that obeys exactly all postulates of the kinetic-molecular theory
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Ideal gas equation
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The product of the pressure and volume of an ideal gas is directly proportional to the number of moles of the gas and the absolute temperature
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Kinetic-molecular theory
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A theory that attempts to explain macroscopic observations of gases in microscopic or molecular terms
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Manometer
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A two-armed barometer
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Partial pressure
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The pressure exerted by one gas in a mixture of gases
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Pascal (Pa)
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The SI unit of pressure
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Pressure
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Force per unit area
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Standard molar volume
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The volume occupied by one mole of an ideal gas under standard conditions
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Standard temperature and pressure (STP)
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Standard temperature 0C (273.15K) and standard pressure, one atmosphere, are standard conditions for gases
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Torr
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A unit of pressure
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Universal gas constant
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The proportionally constant in the ideal gas equation, PV=nRT
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van de Waals equation
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An equation of state that extends the ideal gas law to real gases by inclusion of two empirically determined parameters, which are different for different gases
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Vapor
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A gas formed by boiling or evaporation of a liquid or sublimation of a solid; a term commonly used when some of the liquid or solid remains in contact with the gas
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Vapor pressure
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The pressure exerted by a vapor in equilibrium with its liquid or solid
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