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The study of the composition, structure, and properties of matter, the processes that matter undergoes, and the energy changes that accompany these processes.
A substance that can be broken down into simple stable substances. Each is made from the atoms of two or more elements that are chemically bonded.
Depend on the amount of matter that is present. Include: Volume, mass and the amount of energy in a substance.
Do not depend on the amount of matter present. Include: Melting point, boiling point, density, and ability to conduct electricity and to transfer energy.
A characteristic that can be observed or measured without changing the identity of the substance.
A change in a substance that does not involve a change in the identity of the substance. For example: Grinding, cutting, melting and boiling a material.
A high-temperature physical state of matter in which atoms lose most of their electrons, particles that make up atoms. An important fourth state of matter. Found in fluorescent bulbs.
A substance's ability to undergo changes that transform it into different substances.
Chemical Change or Chemical Reaction
A change in which one or more substances are converted into different substances.
A blend of two or more kinds of matter, each of which retains its own identity and properties.
Mixtures that are uniform in composition. They have the same proportion of components throughout.
A logical approach to solving problems by observing and collecting data, formulating hypotheses, testing hypotheses, and formulating theories that are supported by data.
A specific portion of matter in a given region of space that has been selected for study during an experiment or observation.
More than a physical object; it is often an explanation of how phenomena occur and how data or events are related. They may be visual, verbal or mathematical.
A ratio derived from the equality between two different units that can be used to convert from one unit to the other.
A mathematical technique that allows you to use units to solve problems involving measurements.
Refers to the closeness of measurements to the correct or accepted value of the quantity measured.
Refers to the closeness of a set of measurements of the same quantity made in the same way.
Calculated by subtracting the accepted value from the experimental value, dividing the difference by the accepted value, and then multiplying by 100.
In a measurement, consists of all the digits known with certainty plus one final digit, which is somewhat uncertain or is estimated.
Numbers written in the form M x 10 to the nth power, where the factor M is a number greater or equal to 1 but less than 10 and n is a whole number.
Law of conservation of mass
States that mass is neither created nor destroyed during ordinary chemical reactions or physical changes.
Law of definite proportions
That fact that a chemical compound contains the same elements in exactly the same proportions by mass, regardless of the size of the sample or source of the compound.
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.
The smallest particle of an element that retains the chemical properties of that element. All consist of two regions. The nucleus is a very small region located at the center.
A very small region located at the center of an atom. In every atom, it is made up of at least one positively charged particle called a proton and usually one or more neutral particles called neurons. Surrounding this very small region is a region occupied by negatively charged particles called electrons. This region is very large compared to it.
Short-range proton-neutron, proton-proton, and neutron-neutron forces that hold the nuclear particles together.
Atomic Mass Unit
A unit of mass that describes the mass of an atom or molecule; it is exactly 1/12 of the mass of a carbon atom with mass number 12. (Abbreviation, amu)
Average atomic mass
The weighted average of the atomic masses of the naturally occurring isotopes of an element.
The amount of a substance that contains as many particles as there are atoms in exactly 12 g or carbon - 12. Abbreviated mol.
A form of energy that exhibits wavelike behavior as it travels through space. Visible light is a kind.
A particle of electromagnetic radiation having zero mass and carrying a quantum of energy. The energy depends on the frequency of the radiation.
A state in which an atom has a higher potential energy than it has in its ground state.
When a narrow beam of the emitted light was shined through a prism, it was separated into four specific colors of the visible spectrum. Continuous Spectrum
Heisenberg Uncertainty Principle
States that it is impossible to determine simultaneously both the position and the velocity of an electron or any other particle.
Describes mathematically the wave properties of electrons and other very small particles.
A three-dimensional region around the nucleus that indicates the probable location of an elecron.
Specify the properties of atomic orbitals and the properties of electrons in orbitals.
Magnetic Quantum Number
symbolized by m, indicated the orientation of an orbital around the nucleus.
Spin Quantum Number
Has only two possible values - (+1/2, -1/2) - which indicate the two fundamental spin states of an electron in an orbital.
Pauli Exclusion Principle
No two electrons in the same atom can have the same set of four quantum numbers.
Orbitals of equal energy are each occupied by one electron before any orbital is occupied by a second electron, and all electrons in singly occupied orbitals must have the same spin state
One of the elements of Group 18 of the periodic table. (helium, Neon, argon, krypton, xenon, and radon): Noble gases are unreactive.
Any substance that has a definite composition or is used or produced in a chemical process.
This system of measurement is used in science. It has seven base units: the meter (length), kilogram (mass), second (time), kelvin (temperature), mole (amount of substance), ampere (amount of current), and candela (luminous intensity).
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