Classifying Matter. Elements An element is… The simplest pure substance One kind of material Definite properties Found on the Periodic Table of Elements.

Classifying Matter

ElementsAn element is…

The simplest pure substanceOne kind of materialDefinite properties

Found on the Periodic Table of Elements

Compounds and MoleculesA compound is…

A pure substanceOne kind of materialDefinite properties

Two or more elements chemically combined

A molecule is the smallest particle of a compound that has all the properties of that compound

Water is a compoundH2O is a water molecule

MixturesA mixture is…

MatterTwo or more substances Physically combined NOT chemically combined

Types of Mixtures

Heterogeneous MixturesDoes not appear the same throughoutLeast MixedParticles are large and easily separated

Homogeneous MixturesAppears to be the same throughoutWell mixedParticles are small and not easily recognized

Types of Mixtures (cont)

HeterogeneousMixtures

Homogeneous Mixtures

Solutions

A solution is…

A mixtureHomogeneousTwo or more substancesA single physical state

Solutions (cont)Solvent – That part of a solution which doing the dissolving

Solute – That part of a solution which is dissolved Solute Solvent Solution

Gas Gas Air

Gas Liquid Soda Water

Gas Solid Air Filters

Liquid Liquid Antifreeze

Liquid Solid Dental Filling

Solid Liquid Ocean Water

Solid Solid Gold Jewelery

Solutions (cont)

Law of Conservation of Mass Atoms cannot be created nor destroyedMass cannot be created nor destroyedChange results in arrangement of elementsMass will remain constant

H = 1.0001 amu H2O = 17.9992 amuH = 1.0001 amuO = 15.999 amu

Testing Solution ChemistryObject Calculated

MassMeasured

MassNotes

Discuss things like dissolved, in settled on bottom, cloudy, any other observations

Cup

Cup + 100 ml water

100 ml water

100 ml water + 10 g salt

100 ml water + 20 g salt

100 ml water + 30 g salt

100 ml water + 40 g salt

100 ml water + 50 g salt

Testing Solution Chemistry (cont)Questions1. Did your calculated (predicted) results equal your measured results?2. Can you explain any differences?3. In which scenarios were you able to get the salt to dissolve and in which did you have salt

remaining at the bottom of the cup?4. Did the amount of salt dissolved have any affect on your Conservation of Mass results?

Use the following data about a 2-L bottle of Mountain Dew to answer Questions 5 through 8.Mass of Bottle = 55.6 Mass of Bottle + Soda = 2194 gVolume of Soda = 2000 ml Mass of 2000 ml of Soda = 2138.4 gMass of Sodium = 360 mg Mass of Sugar = 276 g

5. The density of water = 1 g/ml. How much should 591 ml of water weigh?6. How much (in grams) “stuff” is dissolved in the water to make it soda?7. How much should a bottle of soda weigh?8. Can you explain your observations and calculations?

Alloys

An alloy is…

A mixtureA solutionTwo metals orA metal and a nonmetal

Suspensions

A suspension is…

A mixtureHeterogeneousNOT a solutionTwo or more substancesParticles large enough to settle and form a sediment

Ingredients and Procedure

2 parts corn starch1 part water1 – 2 drops of food coloring

1. Put corn starch in the cup2. Add the food coloring3. Slowly add water a few drops at a time and

stir

Now for the science…Our cornstarch goo (sometimes referred to as “oobleck” from the Dr. Suess book) is what scientists call a “Non-Newtonian” liquid. Basically, Sir Issac Newton stated individual liquids flow at consistent, predictable rates. As you likely discovered, cornstarch goo does NOT follow those rules – it can act almost like a solid, and them flow like a liquid. Technically speaking, the goo is a SUSPENSION, meaning that the grains of starch are not dissolved, they are just suspended and spread out in the water. If you let the goo sit for an while, the cornstarch would settle to the bottom of the bowl.

So why does this concoction act the way it does? Most of it has to do with pressure. The size, shape, and makeup of the cornstarch grains causes the cornstarch to “lock-up” and hold its shape when pressure is applied to it. People have filled small pools with oobleck and they are able to walk across the surface of it (as long as they move quickly.) As soon as they stop walking, they begin to sink.