Wednesday, October 30 th, 2013 Starting our New Unit! “Characteristics of Matter”

Objectives The Particle Theory of Matter (SOL PS.2a) Elements, Compounds, Mixtures, Acids, Bases, and Salts (SOL PS2.b) Solids, Liquids, and Gases (SOL PS2.c) Physical Properties (SOL PS.2d) Chemical Properties (SOL PS.2e) Characteristics of Matter based on physical and chemical properties (SOL PS.2f)

Agenda Bell Ringer PearsonSuccessNet.com –Brief Tutorial and explanation of expectations/assignments History Lesson –Eurika! Finding Density

Bell Ringer Describe the eraser. Be SCIENTIFIC! Use scientific terminology to describe this eraser and distinguish it from all the other objects in the room. What measurements could you make to better describe this eraser?

Chemistry 101… Now that we know about the PT, it’s time to learn about the elements on the macroscopic scale. –What are the physical and chemical properties of each element? –How do these elements change chemically? Physically?

Pearsonsuccessnet.com Let’s check-out our assignment!

What are Chemical and Physical Properties? The term “property”, indicates a quality that a substance has or is able to do. In some cases, it’s kind of like looking into the future. Physical Properties Chemical Properties Any observations about the substance that don’t deal with the material changing into a new substance The “ability” for the substance to react with other materials.

Where are we now??? What is an element? –A Pure substance, made out of only one kind of atom. What types of chemical bonds have we learned about in this class? –Ionic (transferring electrons) –Covalent (sharing electrons) Elements bond in order to become… –Chemically Stable

Examples Physical Properties Chemical Properties Boiling Point Melting Point Freezing Point Density Conductivity Malleability Color, Shape, Size Is it... – Reactive? – Corrosive? – Toxic/Poisonous?

Chemical and Physical Changes Physical Changes Chemical Changes Boiling Melting Freezing Changing Density Changing Color, Shape, Size Did it... – React? Was it… – Corrosive? – Toxic/Poisonous?

A story There once lived a brilliant scientist/inventor/mathematician named Archimedes (cir. 250 BC)

The King, Hieron II, gave a solid lump of gold to the local goldsmith to form a beautiful crown (wreath).

After some time, Hieron began to think he’d been cheated by the goldsmith. Maybe the crown was not made out of the pure gold that he’d given the goldsmith. But…it did have the SAME MASS…

Hieron asks Archimedes for his help….was the king taken advantage of???

How Does Archimedes Solve the Riddle??? He takes a bath

He figured it out…can YOU?

Looking at our Activity Describe how you found the volume of the rubber stopper. –Your task is to find the density of several objects

Looking at our lab… Describe how you found the volume of a single paper clip. –Volunteer? –Use the displacement method to find the volume of ten paper clips, then divide that volume by 10 to determine the volume of one paper clip!

Data Analysis Rubber stoppers? –Since the rubber stoppers are made out of the same “stuff” (RUBBER), wouldn’t you expect the atoms to be packed equally as tight?

Data Analysis Wooden Blocks? –In some cases, the smaller block was MORE DENSE! It was made out of a type of wood that is more tightly packed than the larger block. SpeciesDensity Oak 0.71 g/cm 3 Poplar 0.6 g/cm 3 Yellow Pine 0.49 g/cm 3

Data Analysis Water? –Density doesn’t change!!! –One drop of water is no more nor no less “tightly packed” than a gallon of water or a swimming pool of water!

Conclusion… Identify a substance? How did old Archimedes do it? Was the crown really made of gold? SubstanceDensity Copper 9.27 g/cm 3 Aluminum 2.88 g/cm 3 HPE 1.48 g/cm 3 Acrylic 1.22 g/cm 3 Water 1.0 g/cm 3 PE 0.92 g/cm 3

Practice Density Problems Density Dilemma

Concluding Questions 1.Density is a measure of mass per unit volume, or more simply a measure of ____________________. 2.Because density is calculated using two independent measurements it is considered a(n) _____________ value. HOW TIGHTLY PACKED! derived

Concluding Questions… My friend and I ran out of gas the other day and had to walk three MILES to get a gallon of gasoline at the gas station. Of course we got thirsty along the way, so when we were there, we purchased a gallon of water to bring back with us (along with the gasoline). Which would you rather carry on the return trip? (water or gasoline)