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• Substance made of one material and has definite properties
• Particles of a substance are all alike
• Same throughout
Pure Substance
• Simplest form of a pure substance
• Cannot be changed into a simpler substance by any chemical process
• Found on periodic table
CompoundElements
Pure Substance
• Atom– Smallest particle of an element– Basic building block of matter
CompoundElements
Pure Substance
• Pure substances made of more than one element
• 2 or more elements chemically combined
CompoundElement
Pure Substance
Sodium: extremely explosive when it comes in contact with water
Chlorine: a poisonous gas
Two Elements
Combine to form…
• Compounds are made of molecules
• Molecule: two or more atoms bonded together
Every water molecule is exactly the same
2 Hydrogens bonded to 1 Oxygen
CompoundElement
Pure Substance
Compounds … continued
• Not always 2 different atoms bonded together
• Oxygen = element
• Oxygen that we breathe is a molecule– O2
Mixture
• Matter that consists of two or more substances mixed together, but NOT chemically combined
• Substances that make up a mixture can be present in varying quantities
• Can be separated by physical means• Methods used to separate a mixture are based
on the properties of its components
Heterogeneous Mixture
• A mixture that does NOT appear to be the same throughout
• “least mixed” of all mixtures
Homogeneous Mixtures
• A mixture that appears to be the same throughout
• “Well mixed” mixture
• Does NOT separate upon standing
Colloid
• A homogeneous-looking mixture in which the particles are mixed together, but NOT dissolved
• Has some characteristics of homogeneous mixtures (particles are evenly spread throughout) and some characteristics of heterogeneous mixtures (particles are not actually dissolved)
Colloid (refer to fig 4-9 on p. 92)
• Actually falls somewhere between a solution (homogeneous mixture) and a suspension (heterogeneous mixture)
• Particles are kept permanently suspended• Particles are relatively large• Will NOT separate upon standing• Examples: mayonnaise, toothpaste, milk,
fog
Alloys
• Homogeneous solutions of metals
• Solid Solution
• Often used in jewelry
• Example – brass: alloy of copper and zinc, Gold jewelry is an alloy of gold and copper
Solution
• Homogeneous mixture of two or more substances
• “best mixed” mixture
• Composed of solute and solvent
Solute
• Substance that is dissolved
• Substance that there is less of– Example: salt is the solute in salt water solution
Solvent
• Substance that does the dissolving
• Substance that there is more of– Example: water is the solvent in salt water
solution
• Since water is used as the solvent most often, it is called the “universal solvent”
Characteristics of a Solution
• Composed of a solvent and solute
• Particles are NOT large enough to be seen
• Does NOT scatter light
• Properties are evenly spread out (for example: color, taste, odor, etc.)
• Types of solutions: Fig. 4-12, p. 94
Properties of Elements, Compounds and Mixtures
Elements Compounds Mixtures
Made up of only one kind of atom
Made up for more than one atom
Made up of more than one kind of
moleculeCannot be
broken down by chemical means
Can be broken down by chemical
means
Can be separated by physical means
Has the same properties as the atoms making it
up
Has different properties from the elements making it
up
Has same properties as the
substances making it up
Has the same properties throughout
Has the same properties throughout
Has different properties throughout
Identify the following with as many terms as apply:
1. Table Salt
2. Brass
3. Iron
4. Trail Mix
5. Gold
6. Water
7. Sugar
8. Mayonnaise
9. Fog
10. Tacos
Homogeneous Mixture
Element
Heterogeneous Mixture
Compound
Colloid
Alloy
Solution