CHEM 201 test 1 vocab

scientific meathod

systematic way to address a question involving a question, research, hypothesis, test, and results

hypothesis

describes a possible explanation

law

statement that describes many observables

theory

confirmed explanation of a law (withstood all attempts to disprove it)

matter

anything that occupies space

mass

the quantity of matter in an object

weight

attractive force between an object and earth

compressibility

the amount a substance can be compressed when squeezed

pure substance

same composition throughout

mixture

combination of two or more substances that are not chemically combined

heterogeneous mixture

not uniform throughout

homogenous mixtures

uniform throughout

physical property

property that does not change the chemical nature of matter: volume, color, smell

chemical property

properties that do change the chemical nature of matter: combustion, reactivity with water

physical change

involved no change in composition: boiling

chemical change

a substance is changed to another: rusting, combustion

extensive property

depends on the size of the sample: mass, volume

intensive property

does not depend on the size of the sample: boiling point, smell

energy

the ability to do work

kinetic energy

energy possessed by matter that is in motion

potential energy

energy possesed by matter because of its gravitational energy

thermal energy

energy related to the temperature of a substance, is a form of kinetic energy

accuracy

agreement of measured values with accepted values

precision

agreement of multiple measured values

law of conservation of mass

mass of reactants and products are the same in a chemical reaction

law of definite proportions

all samples of a pure substance contain elements in the same proportions

law of multiple proportions

if 2 different molecules contain the same 2 elements, the ration of the element masses are small integers

daltons atomic theory of matter

matter is composed of atoms

daltons atomic theory of elements

elements are composed entirely of one type of atom

daltons atomic theory of compounds

compounds contain more than one element but the relative number of atoms is always the same

daltons atomic theory of chemical reactions

atoms do not change in chemical reactions, only the way atoms are joined changes

millikan oil drop summary

oil drops would have x-rays attach reducing charges and cause negatively charged drops to stop falling or even rising

rutherford gold foil experiment

proved that atoms were mostly empty space with a dense nucleus center due to most passing through the foil, and some deflecting when hitting the nucleus

ions

formed by a loss or gain of electrons

cation

positively charged (loss of electrons)

anion

negatively charged (gain of electron)

ionic compounds

cations and anions bound together (metals and nonmetals)