Elements, Compounds & Mixtures
GOAL
• To tell the difference between elements, compounds and mixtures and to give examples of each
Matter• Matter is anything that has
mass and takes up space.
• Matter is made up of many different things:
Substance
A substance is a single kind of matter that has a specific composition and a specific set of properties - for example, color, melting point, texture . . .
Physical Properties
Physical Properties are characteristics of substances that can be observed without changing it into another substance.
Examples: freezing or melting density hardness color
Chemical Properties
Chemical Properties are characteristics of pure substances that describe their ability to change in to different substances.
Chemical Properties
Examples:
Does it burn? (Flammability)Does it combine with oxygen?(Iron does and forms rust.)
What will the substance react with?
Types of substances
• Elements • Simplest, pure substance, one type of atom present– O2, Na, Fe, N2
Elements
There are over 100 elements in the periodic table. Elements all have unique symbols:
Hydrogen: HLithium : LiOxygen : O2
Neon : Ne
Types of substances
• Compound • 1. Made of several different atoms (combined by chemical reaction)– Salt- NaCl– Sugar- C6H12O6
• 2. Different properties from the elements that make them up
Types of substances
• Mixtures • 1. Made of more than one kind of molecule (many compounds)
• 2. Can be separated or pulled apart by physically (they are NOT chemically combined)
• 3. 2 types:– Heterogeneous– Homogeneous
Heterogeneous Mixtures
• You can see the different parts.
• Examples:• Salad• Soil• Bowl of Mixed Nuts
Types of substances
• Heterogeneous Mixtures
• 1. Not the same throughout
• 2. Large easily seen particles that can be separated out
• 3. Heterogeneous liquid mixtures known as suspensions– Settles after standing
• 4. Tacos, salad, italian dressing, pebble/sand mixture
Homogeneous Mixture
• They are so evenly mixed, you can not see the individual parts.
• Examples:• Salt dissolved in water• Brass is a mixture of
copper and zinc
Types of substances
• Homogeneous Mixtures
• 1. Appears same throughout• 2. Well mixed• 3. Won’t settle upon standing,• 4. Tiny unrecognizable particles
–Solutions are homogeneous mixtures
Types of substances
• Homogeneous Mixtures – Won’t settle out
– Cloudy-Scatters light
– Particles mix, don’t dissolve• Milk, lotion, toothpaste
Types of substances
• Homogeneous Mixtures
• Metal Solutionsa) Alloys- solid metal
solutionsb) Gold= copper and goldc) Brass= copper and zincd) Sterling silver= silver
and copper
Types of substances
• Homogeneous Mixtures
• Solutionsa) One substance dissolved in
anotherb) Tiny particles can’t be seenc) Best mixedd) Clear or transparent- light
passes right throughe) Ocean water, lemonade, air