4 What is the composition of matter? Pure SubstanceMixture
5 What is a pure substance? A pure substance has a definite composition (chemical formula).The composition of a substance will have the same percent of elements no matter where the sample was obtained.Water from the Cuyahoga River and water from the Pacific Ocean (once cleaned up) will have the same ratio of hydrogen to oxygen.Oxygen here is the same as in Columbus
6 What is a pure substance? A pure substance, by definition, is an element or a compound.Water is a compound, and thus a pure substance.
8 Element Atom What is an element? a pure substance made of only one kind of atomAn atom is the smallest unit of an element that maintains the properties of that element.ElementAtom
9 Elemental Samples Zinc, copper, lead, carbon, sulfur… anything on the periodic table
10 What is a compound?a substance that is made from the atoms of two or more elements that are chemically bondedhas a definite chemical formulacannot be broken down any farther bysimple physical meanssmallest amount of a compound with all the properties is a molecule
11 Compound Molecule What is a compound? A molecule is the smallest unit of a compound.CompoundMolecule
12 Examples of compounds? Carbon dioxide CO2 Water H2O Sugar C6H12O6 Oxygen O2Table salt NaCl1 molecule of table salt is the smallest amount that is still table salt. Can’t break it down any farther by physical means…
13 What is the composition of matter? Pure SubstanceMixture
14 MixtureA mixture is made up of two or more substances that are not chemically combined.Mixtures can be separated by simple physical means.e.g. sand and salt, salad
15 MixturesTwo mixtures containing the same substances may not have the same proportions.Example: not all salads have the same amount of tomatoes, but they are all salads
16 Water and Food Coloring Mixture Two mixtures of the same substances may have different proportions.
18 Homogeneous MixtureHomogeneous mixtures are uniform in composition, i.e. particles are evenly spread throughout and you can’t see any differencesThey have the same proportion of components throughout.Examples:- Salt water - Sugar water- Air Carbonated water
19 SolutionA homogeneous mixture when two or more substances are evenly distributed in one another.
20 AlloyA solid or liquid mixture of two or more metals (e.g. brass, bronze)Is a solution, because particles are evenly spread
22 Heterogeneous Mixture Heterogeneous mixtures are not uniform throughout; you can see differencesMolecules are not evenly spreadIf the particles settle over time, it’s called a suspension (if they don’t settle, it’s called a colloid)
23 What is a suspension? A mixture in which particles settle over time. Examples: Orange juice with pulp and muddy water
28 What is a colloid?A heterogeneous mixture suspension where the particles are small enough not to settle.May appear to be the same throughout but it is not!Examples:-Fog -Jello-Paint -Smoke-Whipped cream -Marshmallow
29 Tyndall Effect Sometimes the particles are too small to see. Light does not pass through colloids because their particles scatter light.This is called the Tyndall Effect.
30 What is an emulsion? A special case of a colloid A mixture of two immiscible liquids (ones that usually don’t mix)Examples: mayonnaise, butter, whole milk