Flashcards › Unit 1 - Matter and Energy

absolute zero the zero point on the Kelvin temperature scale, equivalent to -273.15 degrees Celsius atom the smallest particle of an element that retains its identity in a chemical reaction binary compound a compound composed of two elements, for example NaCl calorimeter an insulated device used to measure the absorption or release of heat in chemical or physical processes endothermic process a process that absorbs heat from the surroundings physical property a quality or condition of a substance that can be observed or measured without changing the substance's composition exothermic process a process that releases heat to its surroundings Kelvin scale the temperature scale in which the freezing point of water is 273 K and the boiling point is 373K; 0 K is absolute zero kinetic energy the energy an object has because of its motion matter anything that has mass and occupies space physical change a change during which some properties of a material change, but the composition of the material does not change molecule a neutral group of atoms joined together by covalent bonds mixture a physical blend of two or more substances that are not chemically combined heterogeneous mixture a mixture that is not uniform in composition; components are not evenly distributed throughout the mixture homogeneous mixture a mixture that is uniform in composition; components are evenly distributed and not easily distinguished potential energy the energy that exists as a result of position, not motion; stored energy substance matter that has uniform and definite composition; either an element or compound; also called pure substance law of conservation of energy in any chemical or physical process, energy is neither created nor destroyed temperature a measure of the average kinetic energy of particles in matter; determines the direction of heat transfer element the simplest form of matter that has a unique set of properties; cannot be broken down into simpler substances by chemical means compound a SUBSTANCE that contains two or more ELEMENTS chemically combined in a FIXED proportion chemical change a change that produces matter with a different composition than the original matter heat energy that transfers from one object to another becasue of a temperature difference between the objects chemical property the ABILITY of a substance to undergo a specific chemical change Mrs. Woytowich - Unit 1 - Matter and Energy Flashcards