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The hydrologic cycle essay
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The hydrologic cycle essay
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Formal Laboratory Report
The Chemistry of Natural Waters
Submitted by: Yihua Huang
Lab Partners: Leslie Johnson, Thomas Jaramillo,
Andrea Hurtado
Chemistry 111 Section 101
October 19, 2015
TA: Nabeel Ahmed
Section I: Introduction:
Today, hydrologic cycle is one of the most important component to support people’s life. There are more than one billion people are lack of clean drinking water.1 A person need about 80 liters of water every day to maintain a basic quality life.2
The presence of the dissolved cations (like Ca2+, Mg 2+, and other cations) gives water the chemical property called water hardness. Hard water contains very high concentration of dissolved cations. Conversely. Soft water contains very low concentration of
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Owing to hard water can cause a lot of issues in real life. If people use hard water to wash dishes, it can leave spots on the bowls and plates. Also, hard water cause issues a lot for water boilers. The Ca2+ and Mg2+ will form a scale that makes the water boiler inefficient to work. Moreover, because of hard water contains soluble sedimentary rocks like limestone(CaCO3), pipes with scale can reduce the water flow. This problem increases the energy bills about 25%.3
The hardness of water can be determined by many scientific techniques.
Atomic Absorption Spectrophotometry(AA) is useful to determine metals dissolved in a solution. The chemical principle behind AA is the Beer-Lambert Law. It can be easily used to calculate the metal concentration in the water sample. Atoms have energy levels are unique. Atoms need to be matched the energy of light falling on them to be excited.3
EDTA Titration is another technique to determine metals dissolved in water. Different from AA, it analyzed all cations presented in water, instead of just Ca2+ and Mg2+. 3
Another water to determine water hardness is called Total Dissolved Solids (TDS). It measures the amount of residue that was left in a known amount of water after
For this solution, 5 mL of the solution with 2.5 mL of AMV was placed in the cuvette. The cuvette was placed inside of spectrophotometer and the amount of absorbance was recorded. This procedure that involves a solution with a known concentration was repeated for the concentrations:1.0x10-4 M,5.0x10-5 M,2.0x10-5M, and1.0x10-5M.A unknown solution absorbance was measured by putting 5 mL of unknown solution with 2.5 mL AMV in a cuvette. The cuvette was placed in the spectrophotometer and the amount of absorbance was recorded. The procedure that deals with the unknown solution was repeated 2 more times with the same solution and the same amount of solution and AMV.
A cuvette was filled 3/ 4ths of the way and the absorbance measured in a spectrophotometer. The data was compiled as a class and recorded. The Spectrophotometer was blanked using a test tube of distilled water.
The purpose of the lab is to determine the effectiveness of using gravimetric analysis in determining the hardness of a water sample. More specifically, this lab tests for the amount of dissolved substances such as magnesium carbonate and calcium carbonate. The amount of these substances dissolved in water determines water hardness as they contribute cations to water which result in a buildup of scum or solid CaCO3 as a precipitate. All water tends to have a different hardness as it is determined by the geography area of the water as different regions contain different substances that can dissolve into water.
...ed to clean much more effectively. Soft water is much gentler, but it can be criticized as being too “soft”. One is not particularly safer than the other, and it all comes down to a matter of opinion over which one should be used in the household.
The water hardness is most commonly measured using two different units, either parts per million or parts per gallon. The four samples involved in this project are: Filtered water from a water bottle, water from the Spring Creek Park at State College, water from the Janitor’s closet, and tap water from Copper Beech apartment. In this experiment, these samples were subjected to various tests and procedures to determine specific things in each case. These stages were, determination of water hardness by atomic absorption spectroscopy (AA), evaporation of the water to give total dissolved solids, divalent cation analysis by EDTA titration, determination of the hardness of water sample, water softening with a commercial water-conditioning agent in this case resin, and divalent cation removal ion exchange. After all these steps, and after testing all four of the water samples we were able to determine how to get the water hardness from any water sample the factors involved in the hardness levels, as well as its implications depending on what the water wants to be used for. Therefore, for this experiment there is an expectation of having the following
Hard water may also shorten the life of plumbing and water heaters. When water containing calcium carbonate is heated, a hard scale is formed that can plug pipes and coat heating elements. Scale is also a poor heat conductor. With increased deposits on the unit, heat is not transmitted to the water fast enough and overheating of the metal causes failure. Build-up of deposits will also reduce the efficiency of the heating
Richardson, S. Water Analysis: Emerging Containments and Current Issues. Journal of Analytical Chemistry. 2003, 75, 2831-2857.
Water is a necessity for the existence of human beings. Approximately 71 % of the earth is water and it exists in many different forms. From water vapor in the atmosphere, to rivers and lakes on the earth’s surface to glaciers and icecaps to aquifers in the ground. Water is constantly moving from one place to the other and from one state to the other and this process is known as the water cycle. As water evaporates, vapors rise and condense into clouds. The clouds move over the land, and precipitation falls in the form of rain, ice or snow. The water fills streams and rivers, and eventually flows back into the oceans where evaporation starts the process anew. Water 's state (solid, liquid or gas) is determined mostly by temperature. Although water continuously changes states from solid to liquid to gas, the amount of water on Earth remains constant. There is as much water now as there was hundreds of millions of years ago (Project, 1995).
Alkaline in alkaline water refers to the water's pH level. The pH level, in turn, is a measure of how acidic or alkaline the water is. Typically, the measuring scale for the acidity or alkalinity of a substance is 0 to 14. If a substance has a pH level of 1, it is said to be very acidic and a substance that has a pH level of 13 would be considered very alkaline.
Water is a good solvent and picks up impurities easily. Pure water -- tasteless, colourless, and odourless -- is often called the universal solvent. Dissolved solids" refer to any minerals, salts, metals, cations or anions dissolved in water. Total dissolved solids (TDS) comprise inorganic salts (principally calcium, magnesium, potassium, sodium, bicarbonates, chlorides, and sulphates) and some small amounts of organic matter that are dissolved in water. TDS in drinking-water originate from natural sources, sewage, urban run-off, industrial wastewater, and chemicals used in the water treatment process, and the nature of the piping or hardware used to convey the water, i.e., the plumbing. In the United States, elevated TDS has been due to natural environmental features such as mineral springs, carbonate deposits, salt deposits, and sea water intrusion, but other sources may include: salts used for road de-icing, anti-skid materials, drinking water treatment chemicals, storm-water, and agricultural runoff, and point/non-point wastewater discharges. In general, the total dissolved solids concentration is the sum of the cations (positively charged) and anions (negatively charged) ions in the water. Therefore, the total dissolved solids test provides a qualitative measure of the
Each water molecule consists of one oxygen atom and two hydrogen atoms. The oxygen atom (or the apex of the water molecule) bears a slight electronegative charge while hydrogen possesses a more positive one. Because opposite charges attract, the water molecules are drawn together. When an oxygen atom is linked to a neighboring molecule's hydrogen atom, a bond called a hydrogen bond is formed. In an ice crystal the hydrogen bonds to give the shape of the crystal so that the grid of molecules surrounds relatively to large spaces. In a liquid form, water has no such spaces; so ice is less dense and will float on liquid water. If not for this, great bodies of water would freeze from the bottom up without the insulation of a top layer of ice and all life in the water would die.
Softening Hard Water With Sodium Carbonate Prediction ---------- In a preliminary experiment, we discovered that adding 1g. Na2CO3 to hard water softened it slightly. We tested both tap water and distilled water with the sodium stearate and discovered that tap water was far harder than distilled water, we then tested tap water that 1g of Na2CO3 had been applied to. This solution was softer than the original tap water.
In order for the world to function, there are certain cycles that happen all the time that may not be understood. The water cycle occurs on a daily basis and at all times during the day. Evaporation and Precipitation are among the most ...
BOD determines the quality of water by measuring the amount of dissolved oxygen in the samples. The oxygen in the water is usually from photosynthesis of aquatic plants and oxygen from the air that dissolved into the water. Bacteria uses the dissolved oxygen to degrade the organic matters and produce energy for cell maintenance and growth. The Bacteria/micro- organisms will stop growing until the organic matters run out hence the less the organic matters, the better the water quality. The BOD experiment can measure change of dissolved oxygen level and calculate the amount of micro-organism in each sample. [1]
Freshwater in the world makes up only a small portion of the water on the planet. While the percentage of water in the world is nearly 70%, only 2.5% is consumable. Even further, only 1% is easily accessible to basic human needs. According to National Geographic, “by 2025, an estimated 1.8 billion people will live in areas plagued by water scarcity, with two-thirds of the world's population living in water-stressed regions as a result of use, growth, and climate change.” With this current trend, water will become more immersed in environmental, economic, political, and social changes.