Matter and Energy

Frage	Antworten
matter	anything that has mass and occupies space
mass	a measure of the quantity of matter in a sample of any material
energy	the capacity to do work or to transfer heat
kinetic energy	the capacity for doing work directly
potential energy	the energy an object possesses because of its position, condition, or composition
exothermic reaction	a reaction in which energy is released into the surroundings
endothermic reaction	a reaction that absorbs energy from the surroundings
Law of Conservation of Matter	There is no observable change in the quantity of matter during a chemical reaction or during a physical change.
scientific (natural) law	a general statement based on the observed behavior of matter to which no exceptions are known
Law of Conservation of Matter and Energy	The combined amount of matter and energy in the universe is fixed.
macroscale	a frame of reference used to describe matter that can be seen, handled, and manipulated
nanoscale	a frame of reference used to describe matter that cannot be seen or handled
Dalton's Atomic Theory (1)	1. An element is composed of extremely small, indivisible particles called atoms.
Dalton's Atomic Theory (2)	2. All atoms of a given element have identical properties that differ from those of other elements.
Dalton's Atomic Theory (3)	3. Atoms cannot be created, destroyed, or transformed into atoms of another element.
Dalton's Atomic Theory (4)	4. Compounds are formed when atoms of different elements combine with one another in small whole-number ratios.
Dalton's Atomic Theory (5)	5. The relative numbers and kinds of atoms are constant in a given compound.
atom	the smallest part of an element that maintains its chemical identity through all chemical and physical changes
fundamental particles	the basic building blocks of atoms
atomic number	the number of protons in the nucleus
molecule	smallest particle of an element or compound that can have a stable independent existence
solid	matter that is rigid, has a definite shape, and whose volume does not vary much with changes in temperature and pressure
liquid	matter that flows, assumes the shape of its container up to the volume of the liquid, and whose volume is hard to compress
gas	matter that occupies all parts of any vessel in which they are confined, capable of infinite expansion, and whose volume is compressed easily
chemical properties	properties that are exhibited by matter as it undergoes changes in composition
physical properties	properties that can be observed in the absence of any change in composition
extensive properties	properties that depend on the amount of matter present
intensive properties	properties that are independent of the amount of material present
chemical change	a change in which one or more substances are used up, formed, and energy is absorbed or released
physical change	a change in which no change in chemical composition occurs
mixture	combinations of two or more pure substances in which each substance retains its own composition and properties
heterogeneous	a mixture in which the substances are not uniform throughout
homogeneous	a mixture in which the substances are uniform throughout; also known as a solution
substance	cannot be further broken down or purified by physical means, is matter of a particular kind, and each substance has its own characteristic properties that are different from the set of properties of any other substance
compound	a substance that can be decomposed by chemical means into simpler substances, always in the same ratio by mass
element	a substance that cannot be decomposed into simper substances by chemical changes
Law of Definite Proportions (Constant Composition)	Different samples of any pure compound contain the same elements in the same proportions by mass.
weight	a measure of the gravitational attraction of earth for the body which varies with with distance from the center of the earth
kilogram	basic unit of mass in the SI system; the mass of a platinum-iridium cylinder that is stored in a vault near Paris
meter	standard unit of length in the SI system; the distance light travels in a vacuum in 1/299,792,468 second
scientific notation	the notation used to record/calculate large or small numbers
exact numbers	numbers obtain by counting or from definitions
significant figures	digits believed to be correct by the person who makes a measurement; see rules of significant figures
significant figures (1)	1. Nonzero digits are always significant.
significant figures (2 & 2a)	2. Zeroes are sometimes significant, and sometimes they are not. 2a. Zeroes at the beginning of a number (used just to position the decimal point) are never significant.
significant figures (2b, c, &d)	2b. Zeroes between nonzero digits are always significant. 2c. Zeroes at the end of a number that contains a decimal point are always significant. 2d. Zeroes at the end of a number that does not contain a decimal point may or may not be significant.
significant figures (3)	3. Exact numbers can be considered as having an unlimited number of significant figures. This applies to defined quantities.
significant figures (4)	4. In addition and subtraction, the last digit retained in the sum or difference is determined by the position of the first doubtful digit.
dimensional analysis	unites must always accompany the numeric value of a measurement, whether writing about quantity, talking about it, or using it in calculations
temperature	measurement of the intensity of heat of a body
heat	a form of energy that always flows spontaneously from a hotter body to a colder body
kelvin	the unit used in the SI system to measure temperature
joule	the unit used in the SI system that measures energy and work
specific heat	the amount of heat required to raise the temperature of one gram of a substance one degree Celsius (and Kelvin) with no change in phase
heat capacity	the amount of heat required to raise a body's temperature 1 Celsius

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