chemistry unit 6

standard unit of volume

cubed meter, not liter

where to read volume from

bottom of meniscus

estimate

best guess of adding a digit beyond the marks

- typically 5

Accuracy vs. Precision

accuracy: how close experimental value is to accepted value; precision: how closely measured values agree with each other

error formula

actual - experimental

difference between states of matter

they are all different because of the arrangement of particles /how free they are to move determined by IMFs

Solids

Definite shape and volume

in patterns

can't be compressed easily

particles are locked together and not free to move

matter w strongest IMFS

solids: ionic, metallic, polar covalent

liquids

definite volume but indefinite shape, no pattern

cannot be compressed easily

moderate IMFS: mostly polar covalent

close together particles but free to move

gases

Indefinite volume and shape

can be compressed into smaller volumes

particles far apart with total freedom

weakest IMFS at exclusively non polar covalent, little attraction

how to change from one phase to the next

adding/removing heat

when are LDFs stronger

atoms and molecules are larger

traits of LDFS (3)

low melting point, low boiling point, likely insoluble

traits of dipole-dipole

likely soluble due to polarity, higher MP and BP

strongest IMF

ionic. highest mp and bp, soluble in water

Strongest covalent bond

hydrogen bonding

what happens if energy is added to matter?

particles move faster = kinetic energy

what does temperature mean

average kinetic energy of the particles in a sample of matter

what happens during a phase change

heat is added but temp is the same, kinetic energy isn't changing and particles don't move faster

- arrangement of PARTICLES changes and potential energy moves

physical properties

can be measured without changing composition/identity of substance: density, MP, BP

- how substances are identified

physical change

composition is the same: melting, boiling, cutting, slicing, reshaping

chemical change

new material is formed. can be during a chemical reaction. new properties

chemical properties

characteristics that can only be observed during chemical changes: flammable or corrosive

substance

a unique material/chemical that has a set of properties

elements

simplest form of matter that can't be broken down, made of atoms

compounds

combination of elements to form a substance that can be broken down, over one element

molecules

combination of atoms that create a compound

formula

list of the atoms in a molecule

how can energy change matter (2)

composition of matter = chemical reactions

state of matter = IMFs

kinetic theory (2)

all matter consists of tiny particles that are in constant motion

potential energy in states of matter

stored energy that is determined by the arrangement of the particles

when temperature rises in response to heat...

kinetic energy of the particles increases

when the temperature doesn't rise while heating...

PE is changing

kelvin temperature

directly proportional to the average kinetic energy of the particles of the substance. shifted up 273 degrees

absolute 0

most minimum kinetic energy

composition

arrangement/combination of elements that form a chemical

homogenous

the matter is UNIFORM with only one composition

heterogenous

the matter is not uniform and different parts have different compositions

substances

homogenous materials with ONE unique composition

how are compounds combined

substances that contain more than one element combined chemically

particle of a compound

molecule

particles of all matter are in ____

constant motion

mixtures

A combination of two or more substances that are not chemically combined. occupying the same space at the same time and can be easily separated

are mixtures homogenous or heterogenous

can be either

- one material dissolved in another is uniform/homogenous

- suspensions/colloids are heterogenous

what are liters for

liquids/gases

iterative

Repeating a series of steps over and over until the desired outcome is obtained.

difference between heat and temperature

heat is the energy flow between objects of different temperature, temperature is the measurement of kinetic energy