Activities Review for the Water Unit Test

 The concentration of a solution is expressed in terms of parts of solute to parts of solvent.  So, if we have 10 parts per million as opposed to 100,000 parts per million. Which one is more saturated?  Serial dilution – process of making a solution gradually more dilute (systematic, repeated, same)  Concentration – the amount of a solute per solution Parts Per Million

Testing Water Quality  The Federal Water Pollution Control Act Amendments were enacted in 1972 in response to public demand for water- pollution control to protect humans, wildlife, and aquatic life.

Clean Water Act  Outlined a policy for setting water quality standards and regulating pollutants discharged into waters of the United States.  It became illegal for any person to release any pollutant into water without a permit and allowed the EPA to establish wastewater standards for industries.  Wastewater treatment plants were also funded with this act.

Conducted tests  Appearance/Turbidity – water should be clear and free of any suspended materials.  Odor – Odor should not exceed a threshold value of 3 – noticeable but acceptable.  pH – a pH level between 6.5 and 8.5 is acceptable. pH is a measure of how acidic or basic a substance is. (The reason we test for pH has to do with the environment – if it is too high/low, it can be harmful to plants and animals.

More tests  Iron – Iron levels should not exceed 100 parts per billion (ppb). Levels over 300 ppb affect the appearance and taste of the water.  Nitrates – Nitrate levels should not exceed 10 ppm. Higher levels may cause serious problems in infants.  Copper – levels should not exceed 1.3 ppm. Short periods of exposure to levels over 1.3 ppm can cause nausea and vomiting.

 The Willow Lake Water was turbid, but did not contain detected levels of iron, copper, or nitrate.  The pH was normal because the indicator was green colored.  The cloudiness could have been caused by the soil that washed into the lake with rainwater.  The Fenton River water had a low pH because the indicator turned orange, but did not contain iron, copper, or nitrate. The low pH could have been caused by industrial waste or fertilizer that washed into the river. However, it did NOT appear turbid.  The well water had detected levels of nitrates, which went over the federal standard of 10 ppm. No iron or copper were detected in the well water. The pH was normal and did not appear turbid. Nitrates could have been from fertilizer soaking into the ground and getting into the aquifer. Results of testing

 Based on the results of the tests, Willow Grove needs to treat the groundwater so that the nitrates are removed from the well water. This is important because 50% of the residents drink well water.  Also, the town should figure out what is causing the acid in the river to prevent the levels from rising. The river is used by the town for swimming, boating, recreation, and irrigation, so it is important for it to be clean and safe.  The town should also figure out what is making the lake turbid, but it is still safe to drink because it is treated by the water district to remove the cloudiness. More results

 We conducted two sequential procedures to clean a dirty water sample.  The procedures were similar to the processes of coagulation and filtration that a typical water treatment plant uses to purify water from surface water sources before piping it to homes and businesses. Water Purification

 Coagulation – involves using chemicals to attract contaminants into large clumps  Filtration – traps and separates solid contaminants from the water by making the water flow through filters. Water Purification

 Reservoir – water gathers in a large pool  Coagulation – involves using chemicals to attract contaminants into large clumps  Flocculation – chemicals added to water to attract contaminants – creates clumps  Sedimentation – Involves letting the clumps formed by flocculation sink to the bottom of the water  Filtration – removes solid contaminants from the water  Disinfection – chlorination – disinfectants in the water to remove biological contaminants such as viruses and diseases  Treated Water Reservoir –  Delivered to homes and businesses. Steps

Investigating Solutions of Acids and Bases  Tested water, HCL, and KOH solutions as well as common household liquids to see if they were acids, bases, or neutral using indicators.  Acid/Acidic – the chemical found in a solution that has a pH less than 7. The lower the pH number, the higher concentration of the acid in a solution  Base/Basic (Alkaline) – the substance found in a solution that has a pH greater than 7. The higher the concentration of the base, the higher the pH  Neutral - a solution or compound which is neither acidic nor basic and has a pH of 7.

Indicators  Indicator – a substance that shows whether or how much or another substance is present  pH paper  Changed color depending on pH  Compared to value on pH tube  Universal indicator  Red – Acid  Blue – Base  Green – Neutral  Phenolphthalein  Colorless – Acid/Neutral  Pink – Base

Examples LiquidAcid/BaseLiquidAcid/Base WaterNeutralHCLAcid BleachBaseKOHBase Drain OpenerBasePoweradeAcid CoffeeAcid/NeutralLysolBase VinegarAcid Milk of Magnesia Base Salt WaterBase/NeutralDish SoapBase Lemon JuiceAcidMilkNeutral Alka-SeltzerBaseAmmoniaBase SpriteAcid Pineapple Juice Acid Rubbing Alcohol Acid

Acids, Bases, and the pH scale dchemistry/phscale/

1) When an acid or base is diluted, it becomes more like water. What does this mean?  It’s pH becomes closer to 7. Which contains the characteristics of water. 2) A solution with a pH of 5 is ___ times as acidic as a solution with a pH of 6.  10 3) A solution with a pH of 4 is ___ times as acidic as a solutions with a pH of 6.  100 4) Where are the strongest acids or bases found?  At the ends of the pH scale, or at 1 or 14. Questions

 Neutralization: adding an acid and a base together so that the concentration cancels out and creates a water molecule. H + + OH - H 2 O  Qualitatively: observed colors using the universal indicator. Some got close to green, some overshot the green color and went straight from acid to base or vice versa.  Quantitatively: counted how many drops of acid/base it took to neutralize the other acid/base. Determined which was stronger the acid or the base.  What happens as you add an acid to a basic solution?  Becomes closer to neutral. Overshoot neutral point.  Which solution was more powerful in the investigation, the acid or the base?  The acid because it took a greater number of drops of the base than the acid to produce a neutral solution. Mixing an Acid and a Base

 The ability of an acid and base to neutralize each other is a chemical change.  You change the pH of the product therefore, getting a different substance. Acid-Base Neutralization A B

 Tested electrical conductivity of 7 liquid solutions  Distilled water and Distilled Water + Sugar did not conduct electricity  Introduced to covalent vs. ionic bonds  Covalent bonds: 2 atoms share electrons  Remember you and your friend are both holding onto a basketball  Ionic bonds: a transfer of electrons from one atom to another Remember I am throwing the basketball to my friend. Chemistry of Acids and Bases

 An ion is a charged atom or group of atoms.  Electricity can only be conducted when these ions are moving free within a solution.  A neutral solution has an equal number of these H + and OH - ions.  Distilled water is a poor conductor of electricity because the only ions present are these H + and OH - ions at very low concentrations.  Sugar does not dissolve into ions so it did not conduct electricity.  Tap water is a good conductor due to the presence of dissolved minerals, which are ionic substances.  ACID + BASE SALT + WATER  HCl + NaOH NaCl + H2O  If you neutralized an acid waste, the neutral solution produced could not be safely returned to a lake or river. Chemistry of Acids and Bases