law that states that, in chemical compounds, the ratio of the elements is always the same
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Mixtures
A combination of two or more substances that are not chemically combined
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solution
A homogeneous mixture of two or more substances
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physical property
a characteristic that can be observed or measured without changing the identity of the substance (color, density, odor, melting point, etc)
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chemical property
a property of matter that describes a substance's ability to participate in chemical reactions
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intensive property
a property that depends on the type of matter in a sample, not the amount of matter (temperature, melting point)
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extensive property
a property that depends on the amount of matter in a sample (mass, volume, etc.)
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physical change
A change in a substance that does not involve a change in the identity of the substance (changes of state, like melting, freezing, evaporating, sublimation, and deposition)
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chemical change
A change that occurs when one or more substances change into entirely new substances with different properties.
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metric system
The decimal measuring system based on the meter, liter, and gram as units of length, capacity, and weight or mass.
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Systeme International (SI)
A common metric system of units of measurement used by scientists.
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Meter
SI unit of length
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Kilogram
SI unit for mass
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Mass
A measure of the amount of matter in an object
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Temperature
A measure of how hot or cold something is.
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Celsius scale
water freezes at 0 and boils at 100
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Kelvin scale
SI unit for temperature, water freezes at 273.15 K and boils at 373.15 K (at sea level)
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Volume
(units of length)^3
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no
Is the liter an SI unit?
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density
mass/volume
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exact numbers
Numbers that have no uncertainty and thus do not limit the number of significant figures in any calculation.
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inexact numbers
those numbers whose values have some uncertainty; obtained by measurement
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precision
a measure of how close a series of measurements are to one another
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Accuracy
A description of how close a measurement is to the true value of the quantity measured.
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The Atomic Theory of Matter
the idea that matter is made up of fundamental particles called atoms
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Democritus
Greek philosopher that said all matter is made of tiny particles called "atomos" or atoms
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Law of Conservation of Mass
the law that states that mass cannot be created or destroyed in ordinary chemical and physical changes
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conservation
the principle that properties such as mass remain the same despite changes in the forms of objects
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Law of Multiple Proportions
if two or more different compounds are composed of the same two elements, then the ratio of the masses of the second element combined with a certain mass of the first element is always a ratio of small whole numbers
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Subatomic particles
Particles found within the atom, mainly protons, neutrons, and electrons.
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Cathode rays
streams of electrons that are produced when a high voltage is applied to electrodes in an evacuated tube
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-1.76*10^8 C/g
charge to mass ratio of electron
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Coulomb
SI unit of charge
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Radioactivity
The process in which some substances spontaneously emit radiation
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beta radiation
Radiation that is made up of beta particles; is deflected toward a positively charged plate when radiation from a radioactive source is directed between two electrically charged plates. Of negative charge and low mass
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gamma radiation
High-energy radiation emitted by the nuclei of radioactive atoms. Neutral charge
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alpha radiation
Radiation that is made up of alpha particles; is deflected toward a negatively charged plate when radiation from a radioactive source is directed between two electrically charged plates. High mass, positively charged
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protons
Positively charged particles
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neutron
A subatomic particle that has no charge and that is found in the nucleus of an atom
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electron
A subatomic particle that has a negative charge
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Atomic mass unit
a unit of mass that describes the mass of an atom or molecule
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Angstrom
A unit of length equal to one ten-thousandth 10-10 of a meter.
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atomic number (Z)
the number of protons in the nucleus of an atom
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mass number (A)
the total number of protons and neutrons in the nucleus of an atom
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isotopes
Atoms of the same element that have different numbers of neutrons
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nuclide
a general term for a specific isotope of an element
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Atomic weight
Average of the mass numbers of all isotopes
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Mass spectrometer
an instrument used to determine the relative masses of atoms by the deflection of their ions on a magnetic field
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Periods
Horizontal rows on the periodic table
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groups/families
Vertical columns on the periodic table
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Metals
malleable, ductile, lustrous, good thermal and electrical conductors
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Nonmetals
brittle as solids, dull in appearance, bad conductors of heat and electricity
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Metalloids
Elements that have properties of both metals and nonmetals.
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Formula unit
the lowest whole-number ratio of ions in an ionic compound
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Molecular compounds
compounds composed of molecules
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Molecular formula
A chemical formula that shows the number and kinds of atoms in a molecule, but not the arrangement of the atoms.
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empirical formula
a chemical formula showing the ratio of elements in a compound rather than the total number of atoms
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Structural formula
a formula that shows the arrangement of atoms in the molecule of a compound.
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Ion
A charged atom
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Cation
A positively charged ion
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Anion
A negatively charged ion
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polyatomic ion
A charged group of covalently bonded atoms
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ionic compound
A compound that consists of positive and negative ions
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Chemical nomenclature
the rules used in naming substances
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monoatomic ion
an ion formed from a single atom
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oxyanions
polyatomic ions that contain oxygen
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Stoichiometry
the quantitative relationship between reactants and products in a chemical reaction
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chemical equation
a way to describe a chemical reaction using chemical formulas and other symbols
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reactants
A starting material in a chemical reaction
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products
The elements or compounds produced by a chemical reaction.
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Combination reaction
a chemical change in which two or more substances react to form a single new substance (more reactants than products)
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decomposition reaction
a reaction in which a single compound breaks down to form two or more simpler substances (more products than reactants)
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Combustion reactions
a substance combines with oxygen, releasing a large amount of energy in the form of light and heat. Rapid reactions that produce a flame
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mole
the SI base unit used to measure the amount of a substance
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Avogadro's number
6.02 x 10^23
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molar mass
the mass of one mole of a pure substance
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limiting reactants/ limiting reagents
one or more reactants that are completely consumed
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theoretical yield
the maximum amount of product that can be produced from a given amount of reactant
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actual yield
the measured amount of a product obtained from a reaction
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percent yield
actual yield/theoretical yield x 100
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Solvent
the substance present in the greatest quantity, does the dissolving
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Flashcard (37)