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Chem Vocab Ch 1-2
Chemistry For Today Chapters 1-2 Vocab
Question | Answer |
---|---|
matter | anything that has mass and occupies space |
mass | a measurement of the amount of matter in an object |
weight | a measurement of the gravitational force acting on an object |
physical properties | properties of matter that can be observed or measured without trying to change the composition of the matter being studied |
chemical properties | properties matter demonstrates when attempts are made to change it into new substances |
physical changes | changes matter undergoes without changing composition |
chemical changes | changes matter undergoes that involve changes in composition |
scientific models | explanations for observed behavior in nature |
molecule | the smallest particle of a pure substance that has the properties of that substance and is capable of stable, independent existance. |
diatomic molecules | molecules that contain two atoms |
homoatomic molecules | molecules that contain only one kind of atom |
heteroatomic molecules | molecules that contain two or more kind of atoms |
triatomic molecules | molecules that contain three atoms |
polyatomic molecules | molecules that contain more than three atoms |
atom | the limit of chemical subdivision for matter |
pure substance | matter that has a constant composition and fixed properties |
mixture | a physical blend of matter that can theoretically by physically separated into two or more components |
homogenous matter | matter that has the same properties throughout the sample |
solutions | homogenous mixtures of two or more substances |
heterogenous matter | matter with properties that are not the same throughout the sample |
element | a pure substance consisting of only one kind of atom in the form of homoatomic molecueles or individual atoms |
compound | a pure substance consisting of two or more kinds of atoms in the form of heteroatomic molecules or individual atoms |
basic unit of measurement | a specific unit from which other units for the same quantity are obtained by multiplication or division |
derived unit of measurement | a unit obtained by multiplication or division of one or more basic units |
scientific notation | a way of representing numbers consisting of a product between a single digit number and a 10 raised to a whole number exponent that may be positive or negative |
standard position for a decimal | in scientific notation, the position to the right of the first nonzero digi in the nonexponential number |
significant figures | the numbers in a measurement that represent the certainty of the measurement, plus one number representing an estimate |
exact numbers | numbers that have no uncertainty; numbers from defined relationships, counting numbers, and numbers that are part of simple fractions |
factors used in the factor unit method | fractions obtained from numerical relationships between quantities |
density | the number given when the mass of a sample of a substance is divided by the volume of the same sample |
elemental symbol | a symbol assigned to an element based on the name of the element, consisting of one capital letter or a capital letter followed by a lowercase letter |
compound formula | a representation of the molecule of a compound, consisting of the symbols of the atoms found in the molecule |
nucleus | the central core of atoms that contains protons, neutrons, and most of the mass of atoms |
atomic number of an atom | a number equal to the number of protons in the nucleus of an atom |
mass number of an atom | a number equal to the sum of the number of protons and neutrons in the nucleus of an atom |
isotopes | atoms that have the same atomic number but different mass numbers |
atomic mass unit | a unit used to express the relative masses of atoms |
atomic weight | the mass of an average atom of an element expressed in atomic mass units |
molecular weight | the relative mass of a molecule expressed in atomic mass units and calculated by adding together atomic weights of the atoms in a molecule |
mole | the number of particles contained in a sample of element or compound with a mass in grams equal to the atomic weight. 1 mol is equal to 6.022 x 10^23 particles |