chem 105 study guide!

compound

pure substance made of two or more elements chemically bonded together in a fixed ratio

substance

a form of matter with a definite chemical composition and properties

mixture

a substance made of two or more compounds or elements that are physically combined and can be separated by physical means- no definite composition

molecule

a substance made of two or more atoms chemically bonded together- the atoms can also be the same element

homogenous mixture

cannot see different components of the mixture- it is the same throughout

heterogenous mixture

can see the different components of the mixture- not the same throughout

extensive property

property that depends of amount of matter present

example of extensive property

mass and volume

intensive property

property that doesn’t depend of the amount of matter present- normally the same no matter what

example of intensive property

density, boiling point, freezing point

scientific method

observation, hypothesis, experiment

hypothesis

educated guess

theories

explain and predict different observations that are linked by the same underlying phenomena. Generally accepted as explanations of phenomena

scientific laws

statement of a phenomena with no explanation. Describes what the theory is explaining

law of conservation of mass

mass cannot be created nor destroyed

what is an exact measurement

a number that has an exact value. One that is counted or a conversion unit. They do not affect the number of sig figs

what is the rule with logs and sig figs

the amount of numbers inside of the log is equal to the amount of numbers after the decimal point on the product

atomic mass

the mass of an atom in amu

how to find percent error

(Iactual value-calculated valueI/actual value)x100

To find average atomic mass

take the weighted average of the masses (percent abundance x mass) + (percent abundance x mass)

mass in grams of protons

1.6762 ×10^-14

Mass of neutrons in grams

1.67493 × 10^-14

Mass of electrons in grams

9.10938 ×10^-28

mass of electrons in amu

5.4858 ×10^-4

mass of neutrons in amu

1.0086

mass of protons in amu

1.0073

charge of protons

1.6022 ×10^-19

charge of electrons

-1.6022 ×10^-19

cation

loses electrons- positive ion

anion

gains electrons- negative ion

Law of definite proportions

any given compound is composed of definite proportions by mass of its elements

Antoine Lavoisier

carried out a quantitative experiment of the reaction of phosphorus and oxygen, showing that mass is conserved

law of multiple proportions

for any two or more compounds that are composed of the same elements, for a given mass of one element, the ratio of the other elements are in small, whole number ratios

daltons atomic theory

1. matter is made up of very tiny, indivisible particles called atoms

2. different atoms have different mass

3. atoms combine to form molecules, when they do they combine in whole number ratios

4. atoms of some pairs of elements can combine to form diff compounds called diatomic molecules

5. chem reactions are due to rearrangement of atoms

cathode ray tube

made by jj thomson. he applied a strong electrical current to various substances within the device

what are cathode rays now known as

beams of electrons

what did the cathode ray tube discover

the charge to mass ratio of the electron

what did millikans oil drop experiment do

calculated charge of electron

how to decide charge from oil drop experiment

if given a list of charges and one overall charge, divide the charges in the list by the overall charge and if the answer is a whole number that means that the charge in the list is a possible charge

how was mass of electron decided

millikan used his charge and the mass to charge ratio to figure the charge

alpha particles

positive, small particles that travel very quickly

beta particles

negative

gamma particles

neutral

the average atomic mass represents what

the weighted average mass of naturally occurring isotopes

who made the first widely accepted periodic table

mendeleev

periodic law

when elements are organized in order of the increasing mass, their properties are repeated in a certain interval

periods

horizontal row in order of increasing atomic number

groups

vertical columns

metals

good conductors of electricity and heat, malleable, ductile, lusterous

nonmetals

poor conductors of heat or electricity

metalloids

intermediate properties

group IA

alkaloids. sow, low melting points, low density, highly reactive +1 charged ion

group 2A

Alkaline earth. Harder, higher melting point, denser, reactive. +2 ions

group 6A

chalcogens. -2 ions

group 7A

halogens. Very reactive -1 ions

Group 8A

noble gasses. Colorless, odorless, and mostly inert

diatomic molecules

I, Br, Cl, F, O, N, H

Ionic compounds

made of cations and anions. Normally metals and nonmetals

Covalent or molecular compounds

composed of two nonmetals. Share electrons

mon

1

di

2

tri

three

tetra

4

pent

five

hex

6

hept

7

oct

8

non

9

dec

10

how to name compounds (covalent)

place a prefix on the first element only IF the subscript is more than one. Use a prefix on the second element no matter the subscript number and modify the name to end in ide

name of CO5

Carbon tetroxide

name P2O3

diphosphorus trioxide

sulfur difluoride

SF2

what groups have a definite charge

alkaline, alkali earth, nonmetals,

what atoms have definite charges

silver +1, cadmium +2, zinc +2, gallium +3, alluminum +3

tera

10^12

Giga

10^9

Mega

10^6

Kilo

10³

centi

10^-2

milli

10^-3

micro

10^-6

Nano

10^-9

Pico

10^-12

Femto

10^-15

how many meters are in one inch

.305 m