ObjectivesClassify matter according to its
composition Distinguish among elements,
compounds, homogeneous mixtures and heterogeneous mixtures
Relate the properties of matter to structure
ChemistryInvestigates and explains the structure,
composition, and behavior of matter (how it is made and organized)
It is the WHAT, HOW, and WHY of stuff
Composition and Behavior
But what is matter?Matter is anything that takes up space and has
mass.
…and what is mass?Mass is the measure of the amount of matter
that an object contains.Question: What is the SI unit for mass?
Properties of MatterProperties describe the characteristics and
behavior of matter
How do I determine the properties of matter? Examine it Manipulate it (burn it, dissolve it, mix it) Take measurements
The Macroscopic View of Matter
Macro – prefix – what does it mean?
If you can touch, feel, smell, taste or see it, you are viewing matter from a macroscopic
perspective
The Submicroscopic View of MatterSubmicro – prefix – what do you think it
means?SubmicroscopicSo small that you can’t see it with a powerful
microscope!You are “viewing” the world of atomsNo one has ever seen a single atom, but there
is indirect evidence that supports its existence
Models in ChemistryGive an example of how a model is used?A scientific model is a thinking device that
helps you: 1) Understand and explain the observed
behavior of matter 2) Predict behavior that has yet to be observed Must be supported by experiments
Models in ChemistryWhat do the football team, school choir,
chemistry class, and U.S. Congress have in common?
All composed of people. In the same way aspirin and sucrose have the same kinds of
atoms.
Classifying MatterQUALITATIVE: Observation without
measurementEx: Strong girl, blue dress, Tall man
QUANITATIVE: Observation with measurements
Ex: 100 lbs., 5 dresses, Man is 6 ft. tall
Pure substance or a mixture?PURE SUBSTANCE: Matter that has the
same fixed composition and properties (element or compound)
MIXTURE: Combination of two or more substances in which the basic identity if each substance is not changed - composition is variable
Pure SubstancesELEMENTS: Substances that cannot be
broken down into simpler substances (simplest form of matter)There are ~117 elements, 92 occur naturally
on Earth
COMPOUNDS: Chemical combinations of two or more elements, joined together in fixed proportions with a unique set of properties
MixturesCan be separated through physical processes –
name a phsyical process PHYSICAL CHANGE: A change in matter that
does not involve a change in the identity of the individual substances Examples: freezing, melting, evaporating, cutting
PHYSICAL PROPERTIES: characteristics matter
exhibits without any change in its identityExamples: solubility, melting point, density
Mixtures2 Types of mixtures:Heterogeneous: a mixture with different
compositionsHas clear and distinct regions, called
phases.
Homogeneous: a mixture that is the same throughout (constant composition) also called a SOLUTION
Solutions can have water, gases, solids
Mixtures (cont)ALLOYS: solid solutions that contain metals
and sometimes nonmetals. No water!Ex: Stainless Steel (Fe, Cr, Ni), Brass (Cu and
Zn)
Mixtures (Cont)Aqueous solutions: Contain water.
Solute: The substance that is dissolved.Solvent: The substance that dissolves the solute.
Example: In Kool-Aid what is the solute and what is the solvent?
Organizing elementsPeriodic table organizes elements and provides
chemical information. Periodic tables in textbook on p. 90-91, back
cover. Chemical symbols are universal shorthand- 1 or
2 letter symbols.Ex: O (oxygen) -corresponds to English nameCu (copper)- corresponds to Latin name (cuprum)
CompoundsMore than 10 million compounds (Common compounds on p. 30)
FORMULA: Combination of chemical symbols that shows which elements and how many make up a compound Ex: H2O (water), C12H22O11 (Sucrose)
Group Activity:Pure vs. CompoundHomogeneous vs. Heterogeneous
Grouping/Sorting Matter ActivitySugar and SandSalt and Water Sulfur (S)Stainless SteelMilkSpaghetti and meatballs
ActivityOrganize the matter from the list below
into 2 categories~ PURE and MIXTURE Granola Dihydrogen MonoxideSugar UraniumSterling Silver InkAir Natural GasDiamonds Bronze
ActivityNow…
Separate your PURE matter into elements and compounds.
ActivityNOW…
Separate your MIXED matter into homogeneous and heterogeneous.