Chem Midterm 1 (stuff to memorize)

matter

anything that has mass and takes up space

composition

the kinds of atoms the matter contains(nd number of each atom type present)

structure

the arrangement of atoms in matter

macroscopic domain

in the realm of ordinary-sized objects

microscopic domain

too small to be seen, realm of atoms and molecules

symbolic domain

special language of symbols to represent both macroscopic and microscopic domains

structural formula

H-C-C-H (what type of formula)

molecular formula

C2H3 (what type of formula)

elements and compounds

types of matter (2 broad categories)

pure substance

matter with distinct properties and composition

elements or compounds

2 types of pure substances

mixtures

contains 2 or more substances that are not chemically combined. each substance/component retains its chemical identity and properties

physical means

how can you separate mixtures

elements

substances that cannot be decomposed into simpler substances. composed of only one type of atom

compounds

substances composed of 2 different elements, they are bonded together

law of constant composition

water from any source has the same properties of hydrogen and oxygen

atoms

the smallest building blocks of matter

molecule

2 or more atoms held together by chemical bonds

heterogeneous mixtures

non-uniform composition, properties, and appearances

homogeneous mixtures

have uniform properties and composition (also called solutions)

property

an attribute, quality or characteristic of something

kinetic energy (physics)

energy based upon the motion of a particle

potential energy (physics)

energy based on the position of a particle

kinetic energy (chemistry)

energy described by temperature of sample

potential energy (chemical)

energy described by particle position form other particles (attractions)

physical change

a change that does not alter the identity of a substance, reversible

chemical change

a change that does alter the identity of substance, not reversible

filtration

removes a solid from a heterogeneous mixture

distillation

separates components of a homogeneous mixtures based on boiling point temperature

chromatography

technique used to separate components of a homogeneous mixture that contains substances with different tendencies to stick to surfaces

physical properties

properties determined without changing the identity of a substance

chemical properties

properties that describe all chemical changes that are possible for a substance

Kilo (k)

10^3

Deci (d)

10^-1

Centi (c)

10^-2

Milli (m)

10^-3

Micro (mew)

10^-6

Nano (n)

10^-9

accuracy

degree of reliability of a measurement

precision

degree of reproducibility of a measurement

finite number of SF and a unit

2 things a measurement always has

all digits we know for certain plus one digit we estimate

number of SF we report in a measurement

answers rounded to the lest significant decimal place value

addition of subtraction SF rule

answers rounded to least number of SF in any number used in calculation

multiplication and division SF rule

laboratory balance, g, mg, kg

how mass is measured and units

meterstick, ruler, volumetic glassware, mL, L, cm^3

how volume is measured and units

calculated of or derived, g/mL, g/cm^3

how density is measured and units

thermometer, C or K

how temperature is measured and units

extensive property

these properties depend on the amount of substance present

intensive properties

these properties do not depend on the amount of substance present

dimensional analysis

this method tracks units through a calculation

billiard ball model

this atomic model was the choice for over 100 years, developed by John Dalton

true

T/F: each element is composed of extremely small particles called atoms

false

T/F: all atoms of a given element are identical, but the atoms of one element are different from the other elements

true

T/F: atoms of one element cannot be changed into atoms of a different element by chemical reactions, and new atoms cannot be created nor destroyed in chemical reactions

true

T/F: compounds are formed when atoms of one or more than one element combine, a given compound always has the same relative number and kind of atoms

J.J Thompsons cathode ray experiment

which experiment discovered that rays travel in straight lines and they can be bent by a magnetic or electric field

charge/mass ratio of the electron, and that electrons exist

J.J Thompsons cathode ray experiment determined what

1\.7588x10^8 Coulombs/g

charge/mass ratio of electron

electrons have a negative charge

what did Milan’s Oil Drop experiment determine

smallest increment between 2 data points

most important detail of milikans oil drop experiment

total electric charge of the drop

what did milkman calculate with every drop of charged oil

plum pudding model

new atomic model proposed by Thompson in 1904 after the discovery of the electron

positive and negative charged particles are attracted to opposite magnets and separate

what did Rutherfords investigation of nuclear radiation show

positive

are alpha particles positive or negative

negative

are beta particles positive or negative

no charge

are game particles positive or negative

the nuclear model has a positive charge and nearly all mass in a center of the atom

Rutherfords gold experiment realization

with modified cathode ray tubes

how were protons discovered

neutron

the last discovered subatomic particle

1\.6749x10^-2

mass of neutron

atomic number

number of protons

mass number

number of protons + number of neutrons

charge

number of protons - number of electrons

there can be a different number of neutrons than protons

what does the mass spectrometer prove

separated subatomic particles based on mass

how does the mass spectrometer do

Average Mass = sum of fractional abundance isotope x mass isotope

average mass formula

alkali metals

what group is 1A

alkaline earth metals

what group is 2A

transition metals

what group is 3B-2B (3-12)

halogens

what group is 7A

noble gasses

what group is 8A

left

are metals on the left or right

ion

an atom sized particle containing an unequal number of protons and electrons

anions

neutral atom that gains electrons (typically nonmetals)

cations

neutral atom that loses electros (typically metals)

group number

monoatomic cation charge

group number -8

monoatomic anion charge

replace element ending with -ate

non-metal + oxygen naming

add prefix -per along with -ate ending

extra oxygen in formula naming

change the ending to -ite

one less oxygen than normal naming

add hypo- prefix and change ending to -ite

two less oxygen than normal naming

molecular compounds

formed when atoms share electrons/covalent bonds

H2, O2, N2, F2, Cl2, Br2, I2

what are the 7 diatomic molecules

molecular formula

formula that tells you the number and type of atoms in a molecule

empirical formula

this formula tells you the simplest whole number ratio of atoms

1

mono

2

di

3

tri

4

tetra