matter energy v2

8/4/2019 Matter Energy v2

1/31

Chemistry

The study of the composition,

structure & properties of materials &the changes they undergo.


2/31

6 Branches of Chemistry

Analytical: composition, separation &identification of materials.

Quantitative - measurements

Qualitative - describe w/outmeasurements

Organic: C comps. Inorganic: everything other than C

comps.


3/31

6 Branches of Chemistry-cont.

Physical: physical props of materials

& rxn mechanisms

Biochemistry: materials & processes

in living things

Nuclear: subatomic particles &nuclear rxns


4/31

Scientific Method

1) Observing

State the facts; dont infer

2)Hypothesizing

Classify, categorize

Temporary explanation

3) Theorizing

Repeatedly tested

model

4) Testing Validate, modify or discard theory

5) Law

Summarizes broad spectrum of experiments &

observations


5/31

Matter- anything th takes up space & has mass

Substance - a particular kind of matterw/ a constantcomposition:

Elements & compounds Element - simplest form of matter; 1 kind of atom

118 natural 26 man-made

Metals

> 80; left side of P-table

Good conductors, sonorous, lustrous, high melting pts

Malleable: hammer into shapes

Ductile: draw into wires

Nonmetals

~ 20; right side of table

Good insulators; 11 gases; low melting pts.

Brittle solids


6/31

The type and

the arrangement of particlesdetermines the properties

of the chemical.

Melting Point Boiling Point

Density Color

Malleability Conductivity


7/31

Matter- cont.

Compounds- composed ofmore than 1 kind of atomjoined together chemically; always in definite ratios

Mixtures - a blend of 2 or more substances ea of

wh retains its own identity Homogeneous (solutions) : uniform throughout; 1

phase

Heterogeneous: more than 1 phase with definite

boundaries

Immiscible mixtures : 2 liquids

Suspensions : a liquid & solid


8/31

Evidence of Particles

Diffusion - spontaneous spreading of

particles until evenly distributed

[HIGH] -> [LOW]

Brownian Motion - random motion of

particles due to their bombardment by

molecular particles


9/31

States of Matter- properties relate to kinetics

Solids Definite shape & volume

Particles in fixed, tight pattern

Strong attractive forces

Particles vibrate in place

Liquids

Definite volume: take shape of container

Particles move: slide or flow

Weaker attractive forces


10/31

States of Matter- cont.

Gases

Take shape & volume of containerParticles are rapidly moving

Almost no attractive forces

> 99.9% empty space!!!


11/31

Solid, Liquid & Gases

& Plasma


12/31

Bose-Einstein Condensate

What is temperature anyway??? Measurement of average kinetic energy of a system!

Hot = high KE = fast moving particles

Cold = low KE = slow moving particles

Absolute Zero (Kelvin vs Celsius) 0C = 273 K

Absolute Zero = 0 K

Quantum Blob Particles are fuzzy and begin to overlap quantum

mechanics


13/31


14/31


15/31

Changes of State -cont.

Sublimation -

Solid -> gas

i.e. dry ice, iodine, snow Deposition -

Gas -> solid

Melting & Boiling Pts Characteristic for a sub

Indicate purity


16/31

Kelvin Temp Scale

Provides a direct measure of the average

kinetic E

K = Celsius + 273


17/31

Chem vs. Physical Change

Physical change - state changes; cutting,

pounding, pulling, dissolving

** no new subs. formed

Chemical change - sub undergoes a change:

1 or more new subs form w/ diff characteristics

Signs of a chemical change:

1. 1 or more new subs. 2. E taken in or given off:

Exothermic - E released

Endothermic - E taken in

3. Not easily reversible


18/31

Exo: Outside

A reaction in which energy is released

Gets HOT or

give off LIGHT

Examples:

Burning wood,

Bomb (non-nuclear)


19/31

Endo: within

Reaction where energy is absorbed

Gets COLD

Example:

Ice Packs (NH4NO3)


20/31

Chemical Reactions

Reactants -> (change to or yield)Products

Activation energy - min. amt. of E tostart a chemical rxn

Catalyst - a chem sub th speeds up arxn w/out being consumed

Decreases activation E

Often a transition metal

Place over arrow in an equation


21/31

Energy needed to start a reaction

Match starts with a spark,

but a piece of paper needs a match and a

wooden log start with burning paper.Therefore, each

activation energy

is different.


22/31

Collision Theory

The more successful collisions

(right E & orientation),

the more products produced!


23/31

Law of Conservation of Matter &

Energy Neither matter of E is created in a chemical

rxn, but rather it is transformed.

E can be heat, light, electrical, kinetic, etc.


24/31

Separating Mixtures

Separating Solids fr Liquids - forsuspensions

Filtering

Centifuging

Evaporating the solvent

Crystallizing - evaporate some solvent & cool;

solute will ppt. out


25/31

Separating Mixtures -cont.

Separating a Mix of 2 Solids:

Dissolve 1

Filter suspension

Evaporate

Separate solvent fr soln:

Simple distillation - heat to boiling &

evaporate; solid left behind; collectcondensation


26/31


Separating 2 Liquids:

Separating funnel - for immisciblemixtures

Separates into layers based on density

Tap off different layers

Fractional distillation - for miscible

mixturesHeat to boiling pt. of 1 sub; evaporate &

condense

i.e crude oil


27/31


Separating a mixture ofColoredSubs:

Paper chromatography

Mixture = mobile phase wh is allowed to

pass over a stationary phase

Polarity separates:

Slowest moving = more attraction forstationary phase

Fastest moving = least attraction


28/31

Solutions (homo mixtures)

2 parts to a solution: Solute - in lesser amount

Solvent - in greater amount

Universal Solvent - water!

Unsaturated - a soln th is able to dissolve more

solute

Saturated - added soluted will not dissolve

^ temp = ^ amount of dissolving Supersaturated - contains more solute than a sat

soln can normally hold

Very unstable- tends to precipitate (ppt) excess solute


29/31

Solubility

Depends on temp.

Solubility - max. amt of a sub th will

dissolve in 100g of water at a specified temp ** varies widely for diff subs.

For solids: generally solubility ^ w/ ^ temp

Calculating Solubility - expressed as --g/100g of water at --- temp.


30/31

Solubility - cont.

Solubility Curves

Graph of solubility (g/100 gH2O) vs.

Temp

Find solubility at various temps

Solubility of Gases (in liquids)

*** Solubility decreases w/ increasingtemp

Thermal pollution


31/31

Other Solvents

Alcohol, acetone, gasoline, trichlorethane, etc.

Volatile - evaporate easily at room temp

** flammable & toxic

matter energy v2

Documents