chemistry in the community. safety always use small containers easily handled. never mix chemicals...

Chemistry in the Community

Safety Always use small containers easily handled. Never mix chemicals without teachers permission. Add acid to water, never reverse. Work tray will help contain spills. When selling chemicals, only if directed to do so, hold away from face and wave scent towards nose. Read all labels. Hold coin-top of stoppers between fingers and replace as soon as possible. Notify teacher to clean up spills.

Make sure hose fits securely and has no cracks. Only heat open containers. Always use tongs, never bare hands. Check glass ware for scars or cracks. Never shake thermometer. If thermometer breaks, let teacher know. Use thermometer only in temp range recommended. Lay thermometer down on towel to cool away from lab.

No loose sleeves or clothes in lab. Fuzzy sweaters can easily start on fire. No open shoes, leather closed shoes. ALWAYS WEAR SAFETY GLASSES! Fabrics strong and sturdy Lab apron. Long pants. Tie long hair back. Take off jewelry. No fooling around.

Stand on stool if needed. Immediate medical attention after any cut. Rinse eyes for 15 minutes if you get chemicals in them. Rinse chemicals from hands Get naked for shower. Put out fire in safety shower. No eating or drinking in lab.

Defined: The process of clarifying water in order to make it suitable for release into the environment, or for making it fit for human consumption (potable). Water quantity has its limits: Water supplies on the earth are finite. Current distribution of water is as follows Oceans (saltwater) = 97.2% FRESH Water = 2.8% Glaciers = 2.11% Rivers =.0001% Lakes =.009% Atmosphere =.001% Groundwater =.62% Water Treatment

* With fresh water supplies being so small, water quality is important. This means that water must be cleaned before we use it, and before discharging into the environment it must be cleaned.

PROCESS OF WATER TREATMENT Definition: To clarify water; that is to remove suspended material, is critical to improving the waters quality.

Stages of Water Treatment 1.Large Solid Removal: A screen or grate is used to separate large rocks, trees, etc from water 2.Coagulation, Flocculation, and Sedimentation: A chemical (coagulant) that will cause large suspended particles to form clumps (floc) is added to water. This floc will float or settle out (sedimentation) 3. Filtration: Percolation of water downward through porous material and suspended materials get caught and water passes through. Filter Medial includes sand, gravel, clay, charcoal and screens. Separation works with large pores collecting large particles, with smaller pores, collecting small particles. During filtration, particles may adhere/stick (adsorption) to filter media.

1.Disinfection: The addition of chemicals, usually chlorine to water effort to kill pathogens/microbes/bacteria. 2.Dissolved Solids: These materials will stay with the water because they are dissolved solids in water. Conductivity is a measure of the ability of water to conduct an electrical current. Under most conditions dissolved materials are not removed during water treatment. 3.* To understand Riverwoods Problem: The people of Riverwood must understand the property and behavior of water.

PHYSICAL PROPERTIES OF WATER 1.Water is clear, odorless, and tasteless. Any color, taste or smell is given to water by some outside source. 2.Water is capable of dissolving many different substances. It is defined as the universal solvent. Any substance dissolved in water is said to be in an aqueous solution. 3.* Electrolytes: Act as a conductor of electricity

4. Water is a liquid at room temperature 5. Water has a density of 1g/mL. This doesnt change much as water changes phases. The only unique condition occurs when water freezes. Its behavior at 0 C is unique to water and nothing else. It expands. 6. Water has a narrow range of temperature between its freezing/melting point and boiling point (0-100 C) 7. Polluted water is a mixture. This means some materials are dissolved in water forming a solution. While others are not dissolved and exist in suspension or as a colloid.

Distillation Apparatus

MOLECULAR WATER 1.Composed of elements hydrogen and oxygen 2.Hydrogen and oxygen combine in a 2:1 ratio 3.As water is formed, each hydrogen atom gives up one electron and the oxygen accepts 2 electrons 4.Molecular formula for water is HO

H H O 105 Polar Molecule Structural formula for water is:

Because water has positive and negative poles, this allows for the formation of some new bonds too. These bonds are called HYDROGEN BONDS. Hydrogen Bonds are weak forces that allow two water molecules to be attracted to each other. (See Figure)

The outcomes of hydrogen bond formation are the following: 1.Causes water to behave differently than other materials *Water expands when it becomes ice 2.Requires that water absorbs more energy to change phases(states) *Water will absorb or release huge amounts of heat. *Temp will remain constant 3.Allows water to remain a liquid most of the time O C = Freezing/Melting, 0-100 C= Liquid, 100 C = Boiling Point

**As matter changes phases (states), heat energy must be absorbed

SolidLiquidGas Heat Gain KE Increase KE increase Temp Increase *At the phase change, that is the time when a solid is converting to a liquid and a liquid is converting into a gas, Kinetic Energy remains unaffected. Particle motion doesnt change; as a result the temperature doesnt change. The only factor that changes is the Potential energy. Potential Energy must increase to break hydrogen bonds!

TEMPERATURE: Measure of average kinetic energy of particles in motion, therefore temperature doesnt change during phase change. There is no change in the kinetic energy of the material (water).

Boiling Condensing Solid / Melting Point Boiling Point Liquid -50 C 0 C 100 C 150 C Heat Added Heating- Cooling Curves GasGas Freeze Gas Temperature ( o C) Energy Added

Phase Change Measurements: 1. Latent Heat of Fusion: A measure of heat needed to melt one gram of matter (water) to a liquid. For water this is a lower volume, because hydrogen bonds are needed to be broken; therefore less energy. 2. Latent Heat of Vaporization: A measure of heat needed to vaporize one molecule of matter (water) to a gas. More hydrogen bonds need to be broken; therefore this value is greater for water. Remember at both melting and vaporization TEMPERATURE DOESNT CHANGE!!!!!!!!!! 3. Specific Heat: The amount of energy need to raise the temperature of one gram of a substance one degree Celsius.

Ground Water -Ground Water can be defined as water found in cracks and pores of a rock below the earths surface -The rock through which water can be stored and transmitted (flows, or is pumped out of) is identified as an aquifer. Aquifers can be described by the following conditions: 1. Dimensions: -Vertical Dimension: Depth below ground level. Range from 0 feet -100s of feet. -Horizontal Dimension: Width of the water table. Ranges from 100s of miles. 2. Production: Gallons per mile. 3. Age: Period of time the water has been present in the aquifer (days or years.) 4. Movement: -Vertical Movement: Recharge of ground water. - Horizontal Movement: water flows down hill water will follow contour of the land.

Ground Water Terminology Water Table: The top of an unconfined aquifer; indicates the level below which soil and rock are saturated with water. Confined Aquifer: An aquifer that is bounded above and below by non permeable layer that transmits water significantly more slowly that an unconfined aquifer. The water will rise above the top of the aquifer because the confine aquifer is under pressure. Unconfined Aquifer: An aquifer in which the upper boundary is the top of the water table. Permeable Layer: Portion of aquifer that contains rock material that does not allow water to penetrate freely.

Ground Water Terminology Impermeable Layer: Portion of aquifer that contains rock material that does not allow water to penetrate; often forms the base of unconfined aquifers and the boundaries for confined aquifers. Zone Of Saturation: The part of water bearing formation in which all spaces between soil particles and in rock structures are filled with water. Zone Of Aeration: Portion of unconfined aquifer above the water table where the pore spaces among soil particles and rock formations are filled with air.

Aquifers Of Wisconsin Sand And Gravel Aquifer 1.Covers most of Wisconsin except the south west part of the state (Driftless Area.) 2.Created when the glaciers carried debris across the state and ancient rivers deposited material. 3.Excellent source of water and is used extensively for irrigation. 4.Because of its nearness to the surface it can easily be contaminated.

Aquifers Of Wisconsin Eastern Dolomite(Limestone)Aquifer 1.Sandwiched between the sand/gravel aquifer and a confining layer of (Maquoketa) Shale. 2.Covers the eastern most part of the state from Door County to the Wisconsin and Illinois border. 3.Because of the fractures found in Dolomite the yield of water can vary. 4.Prone to contaminate (again because of the fractures) where ever the water lies to close to the surface.

Aquifers Of Wisconsin Sandstone and Dolomite Aquifer 1.Supplies most of the water for Wisconsin. 2.Covers the entire state except for the North and Central part of the state. * Excellent aquifer since both rocks are very porous, and or permeable

Aquifers Of Wisconsin Crystalline Bedrock Aquifer 1.Made up of the oldest rock in the state. 2. Found as the deepest rock in Wisconsin. 3.Supplies water for North and Central Wisconsin. 4.Shallow wells provide good supplies of water. 5.Deeper wells in the aquifer will yield salty water.

Matter MixturesSubstances -physical combination of matter -nothing new is made -components maintain their individual properties -have uniform and definite composition Suspensions Colloids Solutions Elements Compounds Matter Types Overall Features

-Most basic part of all matter -A chemical combination of 2 or more atoms/elements -Represents the building block of all matter -Its the smallest component is the molecule -Its smallest component is the atom -Can be broken down into the atoms/elements that make it up by chemical means -Over 100 different elements/atoms are known to man Unlike mixtures it has a definite composition Only form of matter that cannot be broken down into something smaller or more basic Example from lab H0 after distillaton Example from lab: none All atoms of a given element are identical with the numbers of protons(+) and electrons (-) All atoms are electrically neutral ElementsCompounds

Chemical Bonding

Formation of Ionic Compounds

Formation of Molecular Compounds (Covalent Bonds)

Polar Covalent

Atomic Structure Average atomic mass 6p + + 6n = 12 (mass number) 12 amu (atomic mass units) Chemical Symbol Element Name Atomic Number = ( number of protons, also number of electrons) * Mass Number = (Protons + Neutrons ) round atomic mass to whole number

Atomic Structure of Carbon Electron Proton Neutron

Reading and Writing Formulas Writing Chemical Formulas Background: Formulas consist of: Element and Element A B (Or) Element and Polyatomic Ion A BC

Ion: Multiple elements combined that behave like one element. When elements want to combine they must lose or gain electrons. Losing electrons Cations Positive Charge Ex: Na + (+) Gaining electrons Anions Negative Charge (-) Ex: Cl - Polyatomic Ions: 2 or more elements behaving as one element that has a positive or negative charge.

Procedure 1.) Write down the symbols of the elements in the compound, as seen on the periodic table Potassium oxide = K O 2.) Place charges next to each symbol as seen on page 33. K O 2 3.) Crisscross the charges K O K O (never write the number 1) (*subscript = tell the number of atoms present : 2 atoms of potassium one atom of oxygen) Ex. Magnesium Phosphate Mg PO Metal

Mg 3 (PO ) 2 *Answer to chemical formula for Magnesium Phosphate

CationAnionFormulaName KClKClPotassium Chloride Ca SO CaPO NH (NO)Ammonium Nitrate Al (SO) Magnesium Hydroxide Calcium Carbonate

Reading Formulas: *If only 2 elements are present: 1.) Read the first element as seen on the periodic table. 2.) Change the ending of the second element to -ide- Al S = Aluminum Sulfide

Look for the metal! *If three or more elements are present: 1.) Read the first element listed as seen on the periodic table. 2.) The second item listed will be a polyatomic ion, and read it as seen on table on p. 33 Zn Co = Zinc Carbonate

Reactants Products Subscript Coefficients Yield State Mg Cl (aq) + 2 Na (s) 2 NaCl (aq) +Mg (s) In a water solution Chemical Equation

Solution Characteristics 1)All solutions have a solute and solvent. a.)Solute: Materials being dissolved(oxygen sugar b.)Solvents: Material that carries out the dissolving process(water) 2)Temperature plays a big role in determining the quantity of solute that will dissolve. 3)At higher temps more solute will dissolve 4)Solubility: The amount of solute that will dissolve in 100 g of water at a given temperature. 5)Therefore at a given temperature, water will dissolve only a certain quantity of solute. (See graph 46) 6)Saturation: The condition created when a solvent is dissolving the max amount of solute possible at a given temperature. 7)Unsaturated: A solvent is dissolving less solvent than it can normally hold at a given temperature 8)Supersaturated: A solvent contains more solute that in can normally hold at a given temperature

Solution Concentration Terms like saturated, unsaturated, and super saturated are sometimes inadequate to describe solution concentration. RIVERS AS SOLUTIONS 1.Water in rivers dissolves many substances, therefore allowing for many ions to be released into the water. 2.Common maters found in river water Limestone bedrock, upon dissolving will release calcium and magnesium ions into water. 3.Salts are naturally found in soil, and they will release different ions into water. 4.Road salt from last year is a source of chloride ions 5.Fertilizer and animal wastes are sources of nitrates and phosphates 6.Photosynthesis will produce oxygen 7.Respiration and decay will produce carbon dioxide and lower oxygen amounts 8.Acidic gases dissolve in water and will lower pH

Balancing Equations *Equations consist of 2 parts: 1.Reactants: Materials found left of the arrow. 2.Products: Materials found right of the arrow. 3.To balance an equation, place coefficients (numbers) in front of either reactants or products, in order to balance the number of atoms on both sides of the equation.

chemistry in the community. safety always use small containers easily handled. never mix chemicals...

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