CHEM FINAL

When does water boil

100 C

When does water freeze

0 C

Conversion factor

a ratio when numerator and denominator are quantities from equality or given relationship.

density

the relationship of mass of an object to its volume

equality

a relationship between two units that measure the same quantity

exact number

a number obtained by counting or by defination

SI

official system of measurement throughout the world except for US

O K

absolute zero

Absolute Zero

the lowest possible temperature

Volume

amount of space occupied by a substance

specific gravity

a relationship between the density of a substance and the density of water

sig figs

numbers recorded in a measurement

peta

10^15

tera

10^12

giga

10^9

mega

10^6

kilo

10³

deci

10^-1

centi

10^-2

milli

10^-3

micro

10^-6

nano

10^-9

pico

10^-12

femto

10^-15

accuracy

how close a measurement is to its accepted or true value

precision

how close together several repeated measurements or events are to one

1 millimeter

cm³ =

calorie

amount of heat energy that raises the temp of exactly 1g of water by exactly 1 C

change of state

transformation of one state of matter to another

chemical change

change during which an original substance is converted into a new substance that has a different comp and new properties

compound

pure substance containing two or more elements w a definite comp

element

a pure substance containing only one type of matter which can’t be broken down by chemical methods.

energy

the ability to do work

energy value

kj obtained per gram of the food types: carbohydrate, fat and protein

gas

state of matter that doesn’t have definite shape or volume

heat

energy associated w the motion of particles in a substance

4.184 J

1 cal

heat equation

relationship that calculates heat given the mass, specific heat and temp change for substance

kinetic energy

energy of moving particles

liquid

state of matter that takes shape of its container w definite volume

matter

the material that makes up a substance and has mass that occupies space.

physical change

change in which physical properties of an substance change but the identity stays the same

physical properties

properties that can be observed or measured wo affecting the identity of the substance

potential energy

type of energy related to the position or comp of a substance

pure substance

type of matter that has definite comp

solid

state of matter that has its own shape and volume

SH

quantity of heat that changes the temp of exactly 1g of a substance by exactly 1 C

elements and compounds

the 2 types of pure substances

mixture

two or more different substances physically mixed, not combined

homogeneous mixture

comp is uniform throughout sample

heterogeneous mixture

comp is not uniform throughout sample

atomic mass

weighted average mass of all the naturally occurring isotopes of an element

atomic number

number that is equal to the number of protons in an atom

isotope

atom that differs only in mass number from another atom of the same element. Same atomic number but different number of neutrons.

mass number

total number of protons and neutrons in the nucleus of atom

periodic table

arrangement of elements by increasing atomic number such that elements having similar chemical behavior are grouped in vertical columns

mass number/atomic number

how to write isotypes

Dmitiri Mendeleev

created the periodic table

John Dalton

developed atomic theory

Thomson

discovered electrons using cathode rays; plum pudding

Rutherford

realized that protons were contained in the nucleus; gold foil experiment

atomic size

distance between the outermost electrons and the nucleus

atomic spectrum

a series of lines specific for each element produced by photons emitted by electrons dropping to lower energy levels

electromagnetic radiation

forms of energy such as visible light, microwaves, radio waves, infrared, ultraviolet light, and X-rays that travel as waves at the speed of light

electromagnetic spectrum

arrangement of types of radiation from long to short wavelengths

electron configuration

list of the number of electrons in each sublevel within an atom, arranged by increasing energy

frequency

number of times the crest of a wave pass a point in 1 sec

ionization energy

energy needed to remove the least tightly bound electron from the outermost energy level of an atom

metallic character

measure of how easily an element loses a valence electron

photon

packet of energy that has both particle and wave characteristics and travels at the speed of light

valence electrons

electrons in the highest energy level is the same as the principle quantum number

wavelength

distance between adjacent crests or troughs in a wave

crest

highest point of a wave

through

lowest point of an wave

pauli exclusion principle

each orbital can hold max 2 electrons

aufbau princple

electrons added first to oorbitaks w lowest energy levels, building by adding electrons to levels w higher energies

molecular compound

combination of atoms in which stable electron configurations are attained by sharing electrons

molecule

smallest unit of two or more atoms held together by covalent bonds

covalent bond

sharing of valence electrons by atoms

polyatomic ion

group of covalently bonded nonmetal atoms that has an overall electrical charge

formula unit

group of ions represented by the formula of an ionic compound

mass percent comp

percent by mass of the element in a formula

molar mass

equal to sum of the masses of the elements in the formula

molecular formula

actual formula that gives the number of atoms of each type of element in a compound

chemical equation

shorthand way to represent a chemical reaction using chemical formulas to indicate the reactants and products and coefficients to show reacting ratios

oxidation

loss of electrons by a substance

reduction

gain of electrons by a substance

actual yield

actual amount of product produced by reaction

endothermic reaction

reaction were in the energy of the products is higher than that of the reactants

exothermic reaction

reaction were in the energy of the products is lower than that of the reactants

Hess’s law

heat can be absorbed or released in a single chemical reaction or in several steps

law of conversion of mass

in chemical reaction, the total mass of the reactants is equal to the total mass of the products; matter is neither lost nor gained

limiting reactant

reactant used up during chemical reaction, which limits the amount of product that can form

melting point

particles of a solid gain sufficient energy to overcome the attractive forces that hold them together

heat of fusion

energy that must be added to convert exactly 1 g of solid to liquid at the melting point

heat of vaporzation

energy that must be added to convert exactly 1 g of liquid to gas at its boiling point

heating curve

diagram showing the temp change and changes of state of a substance as its heated

cooling curve

diagram of cooling process in which temp decreases as heat is removed

sublimation

particles on surface of a solid change directly to a gas w no temp change and wo going into the liquid state

deposition

gas particles change directly to a solid