Chapter 13: Rocks & Minerals : Chapter 13: Rocks & Minerals
Basic Terms : Basic Terms Lets refresh our memory with some basic chemistry terms before we proceed!!
Atomic Number : Atomic Number Number of protons found in the nucleus
Also the number of electrons
Mass Number : Mass Number Number of protons and neutrons
Atomic Weight : Atomic Weight Average atomic mass of an element
Matter : Matter Anything that takes up space, has mass, and can be weighed.
3 states:
Solid
Liquid
Gas
Slide 8: Solid:
Has a definite shape and volume
Liquid:
Definite volume; takes the shape of the container
Gas:
No definite shape or volume; takes shape and volume of its container
Element : Element Pure substance that can’t be broken down into other elements (hydrogen and oxygen)
108 elements on periodic table
First 92 are “natural elements”
Atom : Atom Smallest piece of an element that is still recognized as an element
Contains:
Protons= + charge
Neutrons=no charge
Electrons= - charge
Chemical Symbol : Chemical Symbol One or two letter abbreviations for an element.
Hydrogen: H
Carbon: C
Oxygen: O C6H12O6
Compound : Compound Substance that contains two or more elements bonded together
Ex:
Water (H and O)
Table Salt (Na and Cl)
Molecule : Molecule Smallest unit of an element or compound that can exist by itself
Molecules of Elements
Hydrogen= H2
Oxygen= O2
Molecules of Compounds
Water= H2O
Formula : Formula Tells the # of atoms of each element that combine to make a molecule
Water= H2O
Two atoms of hydrogen are shown by the subscript 2
One atom of oxygen, so no subscript is present
Mixture : Mixture A mixture of two or more kinds of matter that are not chemically bonded to each other
13-2: What is a Mineral? : 13-2: What is a Mineral? A naturally occurring, inorganic solid that has a definite chemical composition and crystal structure
Crystal- flat sides that meet in sharp edges and corners
Formation & Composition : Formation & Composition Minerals come from cooled magma
2500 kinds of minerals; some are easy to find and others are rare
Identifying Minerals : Identifying Minerals Physical Properties are used to identify minerals:
Color- always a reliable way to identify minerals.
However, color can change do to pollution, heat, and cold
Luster : Luster The way a mineral reflects light from its surface
Non-metallic luster:
Don’t have much of a reflection; known as glassy, pearly, and dull
Hardness : Hardness The ability to resist being scratched
Most useful properties for identifying a mineral
Numbered 1-10.
1-Talc-softest
10-Diamond-hardest
Streak : Streak Color of powder scraped off when it is rubbed against a hard, rough surface
Streak may be a different color than the mineral itself.
Density : Density Amount of matter in a given space
Mass per volume
Density of a mineral is always the same
Denser material feels heavier
Crystal Shape : Crystal Shape Minerals have a crystal shape that results from the way the atoms or molecules come together as the mineral is forming
Cleavage & Fracture : Cleavage & Fracture Describe how the mineral breaks along flat surfaces. Ex: Halite
Most minerals break along a rough or jagged surface. Ex: Quartz
Special Properties : Special Properties Magnetite: Naturally magnetic
Halite:
Tastes salty
Sulfur:
Smells like rotten eggs
13.3: Uses of Minerals : 13.3: Uses of Minerals Minerals are raw materials used for a wide variety of products from dyes to dishes and from table salt to televisions
Ores : Ores Minerals or a combination of minerals from which metals and nonmetals can be removed in usable amounts
Metals : Metals Elements that have shiny surfaces and are able to conduct electricity and heat
Ex: Iron, lead, aluminum, copper, silver, and gold
Slide 32: Copper: Pipes and electrical wire
Aluminum: Cans, foil, motors, and airplanes
Silver & Gold: Jewelry
Copper & Zinc: Brass
Nonmetals : Nonmetals Elements that have dull surfaces and are poor conductors of electricity and heat
Some are removed from the Earth and others must be processed
Slide 34: Sulfur: Most useful nonmetal.
Matches
Medicines
Fertilizers
Iron
Steel Production
Gemstones : Gemstones Hard, beautiful, and durable substances that can be cut and polished for jewelry and decoration
Gem: Cut and polished gemstone
Slide 36: Most valuable: Diamonds, rubies, and emeralds
Semiprecious: Amethysts, garnets, and turquoises
13.4: What is a Rock? : 13.4: What is a Rock? Building blocks of the Earth
They form beaches, mountains, the ocean floor, and Earth’s crust
Igneous Rocks : Igneous Rocks Originally hot, fluid magma within the Earth
Latin word Ignis: Means fire
Sedimentary Rocks : Sedimentary Rocks Formed from particles that have been carried along and deposited by wind and water
Sediments : Sediments Bits of rock in the form of mud, sand, or pebbles
Include: Shells, bones, leaves, stems, and other remains of living things
Over time the particles become pressed or cemented together to form rocks
Metamorphic : Metamorphic Rocks formed when chemical reactions, tremendous heat, or great pressure change existing rocks into new kinds of rocks
Slide 43: The Rock Cycle
The Rock Cycle : The Rock Cycle Continuous changing of rocks from one kind to another over long periods of time
13.5: Fluid & Fire: Igneous Rocks : 13.5: Fluid & Fire: Igneous Rocks Classified according to their composition and texture
Composition: Minerals of which rocks are formed
Texture: Shape, size, arrangement, and distribution of the minerals
Extrusive Rocks : Extrusive Rocks Rocks formed from lava, also known as volcanic rocks
Ex: Basalt, Obsidian, and Pumice
Intrusive Rocks : Intrusive Rocks Formed deep within the Earth
Formed when magma forces its way upward into preexisting rocks and then hardens
Ex: Granite
13.6: Slowly Built Layers:Sedimentary Rocks : 13.6: Slowly Built Layers:Sedimentary Rocks 3 Categories:
Clastic rocks
Organic rocks
Chemical rocks
According to the origin of materials from which they are made
Clastic Rocks : Clastic Rocks Made of fragments of previously existing rocks
Classified according to their size and shape
Conglomerate: Over a third of a rock is covered in pebbles
Organic Rocks : Organic Rocks Come from organisms; formed directly or indirectly from material that was once living
When they die, their shells collect on the ocean floor and are compacted into rock
Chemical Rocks : Chemical Rocks When a sea or lake dries up, large amounts of minerals are dissolved in the water
The deposited materials create spectacular formations
13.7: Changes in Form:Metamorphic Rocks : 13.7: Changes in Form:Metamorphic Rocks Already existing rocks are buried deep within the Earth
Heat, pressure, and chemical reactions cause their texture and structure to change
Slide 54: Formed from igneous and sedimentary rocks
Under heat and pressure the minerals in the rocks separate into layers
Rocks texture, mineral composition, and chemical composition change
Slide 55: Foliated- Mineral crystals arranged in parallel layers, which are thin and flat, like leaves
Unfoliated- Rocks are banded together and do not break into layers