The boiling point of water at sea level

The boiling point of water at sea level is 100 degrees Celsius. What phase would you expect water to be if it were heated to 110 degrees Celsius? p p p solid, because the molecules are moving more slowly liquid, because some of the molecules are still boiling at 110 degrees gas, all the molecules have enough energy to have escaped at 110 degrees

1 kg of the compound toluene melts at -95○C. What will happen to 500 g of toluene? p p Melt at -47. 5 ○C Melt at -95 ○C Boil at 47. 5 ○C

As warm air rises, it cools, condenses and freezes in the upper atmosphere. What happens as it falls back to Earth? p p p It undergoes no chemical or physical change It undergoes a physical change from solid to liquid It undergoes a physical change from solid to gas It undergoes a chemical change from a solid to liquid

What is a Mineral?

Minerals – Can you SNIFC it? p p Definition: a naturally occuring, inorganic solid, with a crystalline structure and definite chemical composition Mineral must be: n n n Solid Naturally occuring Inorganic Formula (or Definite chemical composition) Crystalline structure

Mineral Characteristics p Solid: n n Minerals are always solid. They have a definite volume and shape.

Mineral Characteristics p Mineral = Natural occurring, inorganic solid that has a crystal structure and a definite chemical composition.

Mineral Characteristics p Natural Occurring: n n Formed by a process in the natural world Mineral Quartz forms naturally as molten material cools and hardens deep beneath Earth’s surface.

Mineral Characteristics p Inorganic: n n Minerals cannot form from materials that were once part of a living thing. For example, coal forms naturally in the crust, but it is not a mineral because it comes from the remains of plants.

Inorganic p INORGANIC: n p Consist of non-living material ORGANIC: n Consist of living or once living material Coal—made by carbon atoms from ancient trees—trees are living—not a mineral--organic Gold—made by gold atoms —mineral--inorganic

p p Organic? OR inorganic? ORGANIC VEGTABLES

Organic vs Inorganic As a result things like pearls, coral, coal and amber are not considered minerals. Also included in the “NOT a Mineral List” are teeth, bones, sea shells and even kidney stones. Barite Rose - A flower like growth of Barite crystals.

Formula or Definite chemical composition p Any given mineral always has the same chemical composition. We say it has a specific formula. Chemical formulas are a way to describe the specific types and amounts of atoms in a substance. n Example: n n Mineral gold: chemical composition Au (gold) Mineral Diamond: chemical composition C (carbon) Mineral halite: chemical composition Na. Cl (sodium and chlorine) Mineral quartz: chemical composition Si. O 2 (one Silicon and 2 Oxygen)

Mineral Characteristics p Definite Chemical Composition: n n n Minerals always contain certain elements in certain amounts. Almost all minerals are compounds. Some elements occur in nature in a pure form…like copper, silver, and gold. O Si O O O Si Si O O

Mineral Characteristics p Crystal Structure: n n n Particles of a mineral line up in a pattern that repeats over and over again. The repeating pattern forms a solid called a CRYSTAL. Crystals have flat sides, that meet at sharp edges and corners.

Crystalline structure p Unique arrangement of atoms in a crystal

Identifying Minerals p p There about 3, 800 minerals in our world! How do geologists identify all of them? ? ?

Identifying Minerals p Each mineral has characteristic properties that can be used to identify it: n n n n Color Streak Luster Density Hardness Crystal Systems Cleavage and Fracture Special Properties

Identifying Minerals p Color: n n n The mineral malachite is always green and the mineral azurite is always blue. No other minerals look quite the same as these! Their color makes them identifiable.

Identifying Minerals p Color: n n Color is easy to observe, but is not the best way to identify a mineral. Which one is GOLD? Gold Chalcopyrite Pyrite (Fool’s Gold)

Identifying Minerals p Streak: n The streak of a mineral is the color of its powder. You can observe a streak by rubbing a mineral against a piece of unglazed porcelain tile.

Write the definition for a mineral in your own words

Identifying Minerals p Luster: n n Luster describes how light is reflected from a mineral’s surface. “Shininess” Luster of Minerals Metallic Glassy Waxy, Greasy, or Pearly Submetallic or Dull Silky Earthy

Identifying Minerals p Density: n n n Density is how much mass is in a given space (or volume). Sometimes you can FEEL density by measuring the difference of the two minerals in your hand. Density = Mass/Volume n To find the volume of a mineral: Place the mineral in water to determine how much water the sample displaces. The volume of the displaced water equals the volume of the sample.

Identifying Minerals p Hardness HARDNESS is defined as the resistance a mineral has to being scratched - its “scratchability”. Hardness tests are done by scratching one mineral against another. The mineral that is scratched is softer than the other. Pyrite Crystals Hardness of 6. 5

Identifying Minerals p Hardness: n n Friedrich Mohs, an Austrian mineral expert, invented a test to describe the hardness of minerals. The Mohs Hardness Scale ranks ten minerals from softest to hardest.

Identifying Minerals Mohs Hardness Scale 1 2 3 4 5 Talc Gypsum Calcite Fluorite Apatite 6 7 8 9 10 Feldspar Quartz Topaz Corundum Diamond

Mineral Identification Basics p PHYSICAL PROPERTIES HARDNESS In this photo, a quartz crystal was rubbed across a glass plate. The result is that the glass plate was scratched. The quartz is harder than the glass. Quartz is harder than glass. HINT: In doing a hardness test try to pick a smooth or flat surface on the mineral to be scratched. Try to pick a point or a sharp edge on the mineral that you think will do the scratching. Glass is usually a good place to start because it is in the middle of the hardness table, it has a flat, smooth surface and it is easily obtained.

Identifying Minerals p Crystal Systems: n n n All minerals are crystal shaped Minerals that have room to grow form complete, perfect crystals. Minerals that grow in tight places form incomplete shapes. Halite has a CUBIC crystal structure.

Identifying Minerals

Identifying Minerals p Cleavage and Fracture: n n n A mineral that splits easily along flat surfaces has the property called cleavage. Most minerals do not split apart evenly. Instead they have a characteristic type of fracture. Fracture describes how a mineral looks when it breaks apart in an irregular way.

Identifying Minerals p Cleavage CLEAVAGE is the property of a mineral that allows it to break repeatedly along smooth, flat surfaces. These GALENA cleavage fragments were produced when the crystal was hit with a hammer. Note the consistency of the 90 o angles along the edges. These are FLUORITE cleavage fragments.

Identifying Minerals p Fracture FRACTURE is defined as the way a mineral breaks other than cleavage. This is a piece of volcanic glass called OBSIDIAN. Even though it is NOT a mineral, it is shown here because it has excellent conchoidal fracture.

Identifying Minerals

p Name 5 Properties of Minerals

Identifying Minerals p Special Properties: n n Magnetism: Magnetite attracts metal like a magnet. Fluorescence: Scheelite is a mineral that glows in ultraviolet light

Identifying Minerals Special Properties: n Optical Properties: Calcite bends light to produce a double image. n Reactivity with Acid: Aragonite reacts chemically to acid.

Mineral Identification Basics p PHYSICAL PROPERTIES HARDNESS MOH’S SCALE OF MINERAL HARDNESS 1. TALC 6. FELDSPAR 2. 3. 4. 5. GYPSUM CALCITE FLUORITE APATITE (*) 7. QUARTZ 8. TOPAZ 9. CORUNDUM 10. DIAMOND OTHER MATERIALS COMMONLY USED: Moh’s scale is a list of minerals with increasing hardness. (*) 2. 5 - FINGERNAIL 3 - COPPER PENNY 4 – Iron Nail 5. 5 - GLASS 6 -6. 5 - STEEL FILE 7 – Ceramic Tile

Observing Mineral Properties p On a separate piece of paper make this table:

Mineral Name 1. 2. 3. 4. 5. 6. 7. 8. 9. 10. 11. 12. 13. 14. 15. Color Streak Luster (use the ceramic tile) (use your notes!) Hardness Cleavage or (harder or Fracture? softer than a penny? )