Exam 1 - Minerals to Mining Flashcards
Test
What is all matter made of?
test
Test
All matter is made up of atoms, and atoms are made up of atomic particles (electrons, protons, and neutrons
why
why
describe an atom
the smallest unit of a chemical element
Atoms have a nucleus composed of neutrons and protons and has a positive charge
Negatively charged electrons orbit around the nucleus in shell-like layers
describe a chemical element and its component parts
pure chemical substance consisting of one type of atom distinguished by its atomic number, which is the number of protons in its nucleus
Elements have equal balance in numbers of positively charged protons and negatively charged electrons. Common examples of elements are iron, copper, silver, gold, hydrogen, carbon, nitrogen, and oxygen
name an defining characteristic of an element
An element is a substance that cannot be broken down into simpler substances by chemical means
what is an element composed of?
An element is composed of atoms that have the same atomic number, that is, each atom has the same number of protons in its nucleus as all other atoms of that element
Each element is assigned a 1-2 letter symbol to represent the element for general use, such as in the writing of chemical formulas (such as H2O used for water)
describe the periodic table of elements
a list of known chemical elements arranged in order by atomic number from smallest to largest and by group chemical properties
108 known elements - 92 are naturally occurring elements (prior to development of artificial nuclear research and development)
The lightest element, hydrogen, has one proton, whereas the heaviest naturally occurring element, uranium, has 92 protons. In general elements on the left side of the periodic table are elements classed metals (highlighted in gray, green, yellow, and pink), and elements on the right (shown in blue) are nonmetals. On the far right in orange are a group of elements know as noble gases.
describe a molecule
Atoms bond together to form molecules. A molecule is a group of atoms bonded together, representing the smallest fundamental unit of a chemical compound that can take part in a chemical reaction
For instance, a molecule of water—chemical formula, H2O —is made up of two hydrogen atoms and one oxygen atom
chemical substance
A chemical substance is a form of matter having constant chemical composition and characteristic properties
describe a chemical compound
A chemical compound is a pure chemical substance consisting of two or more different chemical elements that can be separated into simpler substances by chemical reactions
Chemical compounds have a unique and defined chemical structure; they consist of a fixed ratio of atoms that are held together in a defined spatial arrangement by chemical bonds. All minerals are chemical compounds, but by comparison relatively few compounds are naturally occurring minerals!
types of chemical bonds
minerals are chemical compounds, but by comparison relatively few compounds are naturally occurring minerals
describe a chemical mixture
A mixture is a combination of two or more pure substances in which each pure substance retains its individual chemical properties. Examples of mixtures include rocks, magma (molten rock) air, and seawater
chemical formulas
Chemical formulas are used to describe compounds such as H2O (for water), NaCl (for salt), CO2 (for carbon dioxide)
Chemical formulas may be simple text designations showing the ratio of elements, or may be represented by graphic means showing relationships (orientation and bonding) between elements within molecules
chemical bonds
Molecular compounds are held together on an atomic level by chemical bonds
Chemical bonds are persistent forces of attraction between atoms or molecule caused by electrostatic forces (positive or negative charges) or the sharing of electrons between bonded atoms.
what are the three types of chemical bonds?
ionic bonds, metallic bonds, and covalent bonds
The types of chemical bond influence the physical properties of the molecular compounds they form.
ionic bonds
Molecular compounds held together by ionic bonds are salts. An ionic bond is a chemical bond between two oppositely charged ions
Typically, metals lose valence electrons (loose electrons in their outer shell of orbiting electrons) to become positively charged cations, whereas the nonmetal accepts electrons to become negatively charged anions.
For example, common salt (NaCl) has ionic bonds between sodium (Na+) has a positive charge and chlorine (Cl-) has a negative charge. Salts readily dissolve in water as their charged ions are attracted to parts of water molecules that can also have positive and negative charges. As water evaporates, the ions dissolved in water will precipitate again as salts (Figures 2-6 and 2-7). Natural salts like halite (NaCl) and gypsum (CaSO4) are generally soft minerals and can dissolve in water.
metallic bonds
Metals are held together by metallic bonds
Compounds with metallic bonds transmit electricity
With metallic bonds, the electrons disassociate from orbiting a single atom and become more of a cloud electrons that surround the positively charged nuclei of interacting metallic ions. Metalloids are intermediate between those of metals and solid nonmetals. Although most elements are metals (all those on the left and center parts of the Periodic Table), only a few elements occur naturally in metallic form including gold, platinum, copper, iron, and mercury (in liquid form).
covalent bonding
Molecular compounds held together by covalent bonds are non-metallic compounds
Covalent bonds occur when two or more atoms share orbiting electrons; sharing of electrons, NOT transfer like ionic bonds
visualize overlapping valence shells of electrons
MUCH stronger than ionic bonded minerals
Van der Waals Force
Van der Waals forces (bonds) are weak, nonspecific forces between molecules and include attractions and repulsions between atoms, molecules, and surfaces.
Van der Waals forces are responsible for friction and what makes water sticky.
mass in chemistry
Mass is the property of matter that measures its resistance to acceleration
Roughly, the mass of an object is a measure of the number of atoms within it.
Mass is often confused with weight. Weight is a measure of an amount of mass under the influence of gravity. For instance, a 150 pound person on Earth would only weigh 25 pounds on the Moon because the Moon only has 1/6 the gravity of Earth.
Density is the ratio between mass and volume. It is a measure of how much matter an object has in a unit volume (such as cubic meter or cubic centimeter).
density
density = mass/volume
Usually defined in grams per cubic centimeter - gm/cm3
what are the most abundant elements found in Earth’s natural environment?
The most abundant elements in our physical environment are: H, C, N, O, Na, Mg, Al, Si, P, S, Cl, K, Ca, Fe. In chronological order by atomic number, these symbols are H hydrogen, C carbon, N nitrogen, O oxygen, Na sodium, Mg magnesium, Al aluminum, Si silicon, P phosphorus, S sulfur, Cl chlorine, K potassium, Ca calcium, and Fe iron.
These elements are:
- ingredients of common minerals, rocks, sediments, and soil (solids)
- components of seawater and air (liquids & gases)
- essential nutrients for life (organic compounds).
what are the most common elements in the earth’s crust?
oxygen and silicon are the two most abundant elements in Earth’s crust
compounds that contain some silicon and oxygen are the most abundant in rocks in the Earth’s crust. These compounds occur as common silicate minerals that occur in abundance wherever rocks of certain origins occur on the surface
minerals
- naturally occurring
- inorganic (never living)
- solid with a definite internal arrangement of atoms (crystal structure)
- has to have a chemical formula that only varies over a limited range that does not alter the crystal structure
- The crystal structure of a mineral has a definite chemical composition
rock/stone
- relatively hard
- naturally formed aggregate of mineral one or more minerals
- Rocks are mixtures and may consist of one or more minerals, but may include organic matter and other non-mineral substances, such as gases and water
- makes up the materials of the solid Earth and other rocky planets and moons in the Solar System
what does the mineral composition of rock reflect?
The mineral composition of a rock reflects the physical environment and geologic history where a rock formed
the rock cycle
a graphic and conceptual model used to illustrate common rocks and earth materials and the processes that form or change in the Earth’s crust over time
The rock cycle depicts the series of events in which a rock of one type is converted to one or more other types and then back to the original type (see the general classification of earth materials below)
Both products (rocks and sediments) and processes (such as melting, cooling, erosion, deposition, metamorphism, remelting) are part of this idealized cycle
The passage of geologic time is the essential component, although some processes are much faster than others.
igneous rock
The term igneous applies to rocks or minerals that solidified (crystallized) from molten or partly molten material—referring to magma (molten material underground), or lava (molten material on the surface of a volcano)
The word igneous also applies to the processes related to the formation of such rocks. (Igneous rocks and volcanism are the focus
sedimentary rock
The term sedimentary applies to materials consisting of sediments or formed by deposition
The word sedimentary applies to both the processes and the products of deposition. Sedimentary rocks form from sediments
halite (NaCl): salt
halite (or common table salt, NaCl) which consists of two elements sodium (Na) and chlorine (Cl) that when combined in a repeating arrangement in a crystalline structure
Note that it would take 4 NaCl molecules (4 sodium atom and 4 chlorine atoms) to make of the minimum cubic unit cell representing the crystal structure of halite. The arrangement of atoms in a cubic structure of the mineral, halite, is repeatable whether on an atomic scale or a microscopic scale (as in table salt) or macroscopic (fist-sized chunk)
carbonate minerals
Carbonate minerals have carbonate ions (-1CO3) within their mineral structure. In nature, most carbonate minerals form from the interactions of carbon dioxide and metals dissolved in water
The mineral calcite is perhaps the most amazing mineral. It has many crystalline forms and can form in many geologic settings. It is also an exceeding important mineral resource - it is used in the manufacture of cement, and is used in some manner in the process of manufacturing of thousands of compounds used in industry, including the manufacture of steel and the production of medicines and food. Calcite consists of a crystalline structure composed of molecules of calcium carbonate (CaCO3). Basically, the calcium (Ca) comes from the Earth, and the CO3 comes from the atmosphere, and nearly all the CaCO3 is deposited by biological activity in the oceans and precipitated from water underground.
dolostone and limestone
Calcite is the dominant mineral in the sedimentary rock called limestone. Over time, groundwater rich in dissolved magnesium can seep through limestone, gradually converting calcite to dolomite. As a result, ancient limestone rock formations often contain higher concentrations of dolomite than calcite. If a rock has more that 50 percent dolomite it is called dolostone
observable properties of a mineral
crystal form - color cleavage luster (metallic, non-metallic) diaphaneity (transparent, translucent or opaque) double refraction striations feel odor (smell) taste
Crystal form
many minerals have unique and sometimes obvious crystal structures, however, crystal structure alone may not be enough to identify a mineral
the external expression of the ordered internal arrangement of atoms
color
some minerals have very distinct colors, however, color is not a reliable indicator by itself
E.g.1 many different minscan be brownE.g.2 single min, like quartz can be many colors
cleavage
the tendency of a crystallized substance to split along definite crystalline planes, yielding smooth surfaces
Mica, feldspar, calcite, and selenite gypsum have good mineral cleavage. Flat, smooth, shiny and reflective surfaces on specimens may be either crystal surfaces and/or cleavage
luster
the description of the quality and intensity (sheen or shine) of light reflected off of a mineral, particularly a reflective appearance of the exterior of crystal surfaces and cleavage planes. There are many kinds of luster
how light reflects off of an object
feel
The feel of a rock is not a reliable method of testing minerals, however certain minerals have textures like “soft, silky, satin, smooth, hard, heavy or light” - but these characteristics are poorly definable as a reliable means for identifying minerals
odor
few minerals have an odor. Sulfur-bearing minerals may put off a rotten-egg like smell. Many rocks of sedimentary origin have the smell of petroleum.
taste
halite tastes like salt (because it is NaCl). (Note that tasting minerals and rocks is generally not recommended! Some minerals can be quite poisonous)
hardness
minerals have different durability properties. Depending on mineral chemistry and crystal structure, minerals have varying degrees of hardness
measure of resistance to abrasion (Moh’s Hardnes)
minerals held together by ionic bonds (like halite, gypsum, and calcite) tend to be softer than minerals
magnetism
iron (the natural mineral iron in crystalline form) and magnetite (Fe3O4) are common magnetic rocks, iron-rich meteorites are also magnetic. Figure 2-71 is sample of Diablo Canyon (Arizona) iron meteorite that is highly magnetic.
Many minerals rich in iron are partly magnetic and display measurable magnetic susceptibility that can be useful for geophysical exploration. Large bodies of rock containing iron-rich minerals can be remotely detected below the earth surface, and may be useful for detecting hidden faults, water-filled sedimentary basins, or potentially economically valuable mineral resource deposits. Magnetic susceptibility measurement are used in regional geophysical mapping.
specific gravity
a measure of the density of a mineral. Specific gravity is the ratio of the density of a substance to the density of water
Tests for specific gravity require some laboratory equipment. Specific gravity is a measure of weight with a known volume
streak
color of min when powdered
streak varies less than color, so it is a “better” property
Usually’ metallic mins have dark streaks
Be aware that streak tests can be destructive to mineral samples. The mineral graphite (used in pencils) leaves a black streak
acidic reaction
Calcite fizzes when exposed to mild acid, releasing carbon dioxide gas. Dolomite will fizz in hot acid.
Note that all minerals are chemicals that can react to chemical agents, altering or destroying them. Whereas gemstones are typically durable, the can be susceptible to chemicals added to cleaning fluids
atomic weight
of protons + # of neutrons
fracture
the absence of cleavage
how many minerals are there?
About 4000
40 to 50 new ones named each year
Average University Mineralogy class learns about 300, BUT…
Only about 40-50 rock-forming minerals are common in Earth’s crust
All matter is made up of atoms, and atoms are made up of atomic particles (electrons, protons, and neutrons
why
why
Test
What is all matter made of?
test
Test
