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Matter Properties of Materials o o o

describe materials by listing their properties chemical properties vs. physical properties. intensive properties vs. extensive properties. Classifying properties as extensive or intensive. Extensive properties change when sample size changes; intensive properties don't. Mass of water

100.0 g

10.0 g

Volume of water

0.100 L

0.010 L

25 °C

25 °C

1.00 g/mL

1.00 g/mL

Temperature of water Density of water

States of Matter Gas o o o

Liquid o o

low density easy to expand/compress fills container

o o

o

Solid o o

high density hard to expand/compress takes shape of container

o

high density hard to expand/compress rigid shape

A phase is a region with homogeneous (uniform) properties conversions between states are called "phase transitions" or "changes of state"

Classification of matter uniform properties? no

heterogeneous mixture

yes

fixed composition? no

homogeneous mixture

yes

chemically yes compound decomposable? no

element

Pure substances o

characteristics  percentage composition always the same from sample to sample  melt/boil at a characteristic temperature  note: some compounds decompose before melting or boiling!


o

two types   

elements not chemically decomposable into other elements properties do not vary

 

compounds elements combined chemically in law of definite proportions properties do not vary

Elements   

modern definition: elements are made of atoms that all have the same atomic number obtaining elements from compounds involves chemical change o electrolysis decomposes some compounds into elements o some elements displace others from compounds writing element symbols o first 1-2 distinguishing letters in name used for symbol o only the first letter is uppercase! o memorize symbols derived from ancient names:

Table 11 element symbols derived from ancient names. English name symbol ancient name antimony

Sb

Stibium

copper

Cu

Cuprum

gold

Au

Aurum

iron

Fe

Ferrum

lead

Pb

Plumbum

mercury

Hg

Hydrargyrum

potassium

K

Kalium

silver

Ag

Argentums

sodium

Na

Natrium

tin

Sn

Stannum

tungsten

W

Wolfram


Classification of elements  

periodic table compactly shows relationships between elements features of the periodic table o Periods are horizontal rows on the table. o Groups (or families) are columns on the table.  elements in the same group are called congeners. They have similar chemical properties. o Blocks are regions on the table. important groups: o alkali metals (Group IA, first column )  soft, extremely reactive metals  react with cold water to form hydrogen gas  form +1 ions o alkaline earth metals (Group IIA, second column):  soft, reactive metals  compounds are a major component of earth's crust  form +2 ions o halogens (Group VIIA, next-to-last column):  poisonous and extremely reactive nonmetals  fluorine and chlorine are yellow-green gases  bromine is a volatile red-brown liquid  iodine is a volatile blue black solid  all form -1 ions o noble gases (Group 0, last column)  all are monatomic gases  a. k. a. inert gases; almost completely unreactive Important blocks: o transition metals are the elements in the region from the third to twelfth columns.  hard, dense metals  less reactive than Group IA and IIA o rare earth metals are the elements in the annex at the bottom of the table.  lanthanides (annex, top row)  actinides (annex, bottom row) o main group elements are all elements except the transition and rare earth metals.  group numbers end with "A" o metals, nonmetals, and metalloids (semimetals)  metallic properties  luster  malleability: can be hammered into thin sheets  ductility: can be drawn into wire  conduct heat and electricity well


Allotropes 

one element can occur in several different forms ( allotropes)

Common allotropes of oxygen and carbon. The most stable form at room temperature and pressure is shown in boldface. Element

Allotrope

Oxygen

O, nascent oxygen O2, oxygen gas O3, ozone Graphite

carbon

Diamond 

gaseous elements commonly occur as diatomic molecules (except for the noble gases)

Mixtures 

characteristics o percentage composition varies from sample to sample o components are chemically different and retain properties in a mixture o do not melt/boil at a definite temperature two types o  

heterogeneous mixtures components not uniformly mixed more than one phase

  

homogeneous mixtures components uniformly mixed one phase also called solutions

o

Separating mixtures   

mixture's components have different properties devise a process that selects components with certain properties o density, melting point, boiling point, solubility, reactivity, magnetism, polarity some basic techniques o filtration: select components by particle size o floatation: select components by density o crystallization: select components by solubility o extraction: select components by solubility o distillation: select components by boiling point o chromatography: select components by affinity for a 'stationary phase


Matter Note Sheet