topic: classifying matter
DESCRIPTION
Topic: Classifying Matter. Indicate whether the following changes are physical or chemical. Burning wood Tearing paper Freezing Water Dissolving NaCl in H 2 O Mixing NaCl and SiO 2. Matter. Substances. Mixtures. Heterogeneous Mixtures. Homogeneous Mixtures. Compounds. - PowerPoint PPT PresentationTRANSCRIPT
Topic: Classifying Matter
Indicate whether the following changes are physical or chemical. • Burning wood• Tearing paper• Freezing Water• Dissolving NaCl in H2O• Mixing NaCl and SiO2
Matter
Substances Mixtures
Elements Compounds HeterogeneousMixtures
HomogeneousMixtures
Mixtures Separated by physical methodsCompounds Separated by chemical methods
Can it be separated by physical methods
NO YES
Atoms
Pure Substance
• uniform throughout• Definite composition• Same characteristic properties regardless of
source which are pure substances
Element• Substance that:
• cannot be broken down or decomposed into simpler substance
• only 1 kind of atom• has definite properties
• Formulas have 1 uppercase letter
Cu
F F FF
Cu
Cu
Cu
F2
Particle Diagrams
Atoms of a monatomic (1) element
Molecules of a diatomic (2) element
I
N O F
Cl
Br
These seven elements are always diatomic HH2
N2 O2 F2
Cl2
Br2
I2
Element Song
Big Bang Version sung by Sheldon
Compounds• 2 or more different types of
atoms chemically combined in a definite ratio
• Properties are different from those of elements formed from
• Only Broken into elements by chemical rxn
• Formulas have 2 or more uppercase letters
H
H HO
H
HCl
Cl
Cl
H HO
HCl
H2O
2Na + Cl2 2NaCl
Element or Compound?
Na = element
Cl2 = element
NaCl = compound
Particle DiagramsAtoms of a diatomic (2) compounds
Molecules: Can be elements or compounds – but must contain 2 or more total atoms (can be the
same type or different)
O O
H H
OS S S S
HCl
S S S S
O2
H2O
S8
HCl
Mixtures
• Combo of 2 or more pure substances (elements + elements) (elements + compounds) (compounds + compounds)
• Physically combined not chemically combined
• Each substance retains its own identity and properties
Mixtures• Variable composition• No unique properties
(Think of sugar and salt mixed together)
•Separated by physical methods• May be homogeneous or
heterogeneous
Types of Mixtures• Heterogeneous: NOT UNIFORM
throughout -individual components visible - scatters light (can’t shine light through)
GraniteOil in water Salad
dressing
Suspensions (type of heterogeneous mix.)
• Particles are larger • can be evenly distributed by
mechanical means (shaking the contents) • Settle out on standing
• Homogeneous (aka solutions): UNIFORM composition throughout- individual components not visible
• Solutions in gas & liquid phases transmit light (can shine light
through)• particles not big enough to scatter light • look translucent
RECAP: Solution vs Suspension
• Solutions in gas & liquid phases transmit light
• particles not big enough to scatter light • look translucent
• Suspensions look cloudy • particles big enough to scatter light• settle on standing
Solution(homogenous) vs Suspension(heterogeneous)
CuSO4(aq)
Solution(homogenous) vs Suspension(heterogeneous)
K
O
H
KKK
K
O
O O
K
HO
H HO
H HO
H HO
H HO
H HO
H HO
H HO
HO
F- F
-
F-
F-
F-
F-
F-
F-
O O
O O
Homogenous Mixture:Compounds & elementsBoth in liquid phase
Heterogeneous Mixture:elements & elementsO2 in the gas phaseK in the solid phase
Heterogeneous?
Or
Homogeneous?
Compounds?
Or
Elements?
Solid?Liquid?
Gas?