Chapter 9 and Chapter 11 Narrations
Chapter 9: Acids and Bases
Acids are defined as molecules or ions that are able to donate hydrogen ions to bases. Other authors have defined them as substances that produce hydrogen ions (H+) when dissolved in water. They are therefore proton donors (Brent 10-11). Acids and bases have become important components in biological and environmental systems and industrial processes. In fact, most of items found at home contain either acidic or basic substances. Acidic substances, which include grapefruit, lemons, vinegar and lime, taste tart or sour (Lew 1). Acids can be either diluted or concentrated. Concentrated acids such as sulphuric acids and hydrochloric acid are always dangerous. Dilute acids have unpleasant reactions, but are not dangerous and exist in vinegar, lemons and some soft drinks. On the other hand, for bases, are substances that when dissolved in water will release hydroxide ion (OH-) (Brent 12-14). Generally, bases test bitter, have slippery feelings, change the color of litmus indicator from red to blue and neutralize acids. Some of common substances found at home containing alkaline substances are milk of magnesia, baking soda, toothpaste, washing bleach, soaps, detergents, household ammonia, oven cleaners, drain cleaners, antacids and lye (Lew 1).
However, one should realize that the term dilute/ concentrated acids or bases should not be confused with weak/ strong acids or bases. Diluteness or concentration of an acid or a base will be determined by the number of hydrogen ions or hydroxide ions in a solution. Strong acids refer to how a substance readily gives/dissociates out in water to give out hydrogen ions. For instance, hydrochloric and sulphuric acids are strong because they completely dissociate in water to give out hydrogen ions. Others like acetic acids are weak, as they do not dissociate completely. On the other hand a strong alkaline will be determined with how much it gives out hydroxide ions. Strong bases are potassium hydroxide, sodium hydroxide and lithium hydroxide whilst weaker acids are ammonium hydroxide and diethylamine, (CH3CH2)2NH (see appendix 1). As already explained for a weak acid, not all hydrogen ions will be dissociated in water. Likewise, for weak base, not all hydroxide ions will be dissociated in water (Lew 13).
Neutralization between a base and an acid occurs when exact amount of hydroxide ions and hydrogen ions react to form water. Apart from water, salt will be produced; for instance, when potassium hydroxide reacts with hydrochloric acid, potassium chloride (salt) and water will be formed (see appendix 2) (Brent 28) . Importantly, one should note that although some substances such as neutral ammonium (NH3) may be neutral, they would normally react with water to obtain an extra hydroxide ion so that it becomes NH4+, which is a base (Lew 41).
Molarity
Molarity can be defined as concentration of a solution, which is usually determined, by the number of moles of solute per liter. A mole is a unit of chemical mass defined as 6.022 X 1023 atoms or molecules. The mass of one mole of any substance represents its gram formula mass (Brent 28).
pH Scale
Having talked about weak and strong bases and acids, one should conclusively say that one of the factors affecting their reactions is their concentration of ions, H+ and OH-. The pH scale indicates how acidic or basic a substance is and it is calibrated from 0 to 14. A pH level more than 7 is basic, whilst that less than 7 is acidic. At 7, a substance will be neutral.
In this regard, water is neutral at 7, while battery acids will be between 0 and1 and bleach at 12 (see appendix 3). The pH scale is defined by determining a negative of the logarithm of the hydrogen ions in one molarity of a substance (Brent 6).
Along a pH range scale, are the buffers, which are combinations of weak acid and weak base ions or weak base and weak acid cations. They include blood, whose pH reading is maintained at 7. 4. For Corrosive substances, they will have a pH depending on its use. In most cases, they will have high or lower pH values to dissolve the intended substances (see appendix 4) (Brent 14).
Chapter 11: Water
Water is defined as a transparent, tasteless and odorless liquid, which freezes at zero degrees Celsius, and as a compound, it constitutes 88.812% oxygen and 11.188% hydrogen. It constitutes oceans, rains, rivers, lakes among others. Moreover, it is the only substance that changes in its state without losing its pH value. Its heat of fusion is 80 cal/g, and it is known to have a high surface tension and referred to as excellent universal solvent (see appendix 5) (Likens 1).
Acid Rainfall
This kind of precipitation or rain is usually acidic at elevated levels in hydrogen ions, at low pH, which may have harmful effects on aquatic animals, infrastructure and plants (see appendix 7). It is normally caused when there are high emissions of nitrogen oxide and sulfur dioxide that react with water molecules to produce acids (see appendix 6). Although the two gases may be emitted by industries, they may arise due to lightening and volcanic eruptions. This kind of rain was much prevalent in 1990s, in countries like Greenland, and had large effects to its citizens. It resulted in fish dying, building crumbling and forest drying. To prevent such rains from occurring, countries have been eliminating emissions of the nitrogen and sulfur gases or neutralizing them with lime (Guerrero 8-22).
Shortage of Water
It is important to note that although 70% of the earth is composed of water, it has only 1% of fresh water. As the population continues to grow, it has been noted that the total demand of the product will continue to rise (see appendix 8). This fresh water which is obtained from aquifers and surface water such as lakes, rivers, ponds and rivers encounters competition from household, industry, agriculture/ irrigation, thermoelectric power and so forth (Houston, and Griffiths, 24-17).
Pollution
The 1 % of fresh water is faced with threats from pollutants. Pollution eliminates the natural usefulness of water by adding impurities so that it cannot become suitable for irrigation, washing and drinking. In this regard, the polluting substances may be toxic elements like lead, mercury, Arsenic metals, industrial wastes and household wastes. The government through EPA, in the 1972 act, shifted the responsibility of producing water that is suitable for reuse from the user to the discharger. Therefore, for those who discharge polluted water, they can adopt methods such as oxidation, filtration, sedimentation, and aeration. Industries are much encouraged to produce and use packing materials that are easily biodegradable. Municipalities can also design and institute proper sewerage systems that will have water being collected without any problem (see appendix 9). Otherwise, classical methods such as outhouses and Cesspools are still useful (Houston, and Griffiths 1-13).
Soft and Hard Water
The only difference between hard and soft water is that the former contains dissolved mineral such as magnesium and calcium. In general, this kind of water is not bad for consumption, in fact some expert recommend it to be healthy because of the minerals. However, it may not be suitable for some industrial applications, since it may not be efficient through pipes and suitable for washing. To identify hard water and therefore to differentiate it from soft water, one can observe the way it lathers with soap; hard water makes little form with soap. There are two types of hardness: temporary and permanent. Temporary hardness is caused by magnesium and calcium bicarbonate in water and can be removed through boiling. On the other hand, permanent hardness is caused by magnesium sulfate or calcium sulfate and cannot be treated by boiling, but it requires lime to dissolve the magnesium sulfate or calcium sulfate in water (Likens 45-67).
Works Cited
Brent, Lynnette. Acids and Bases. New York: Crab Tree Publishing Company, 2008.Print.
Guerrero, Peter F. Acid Rain: Emissions Trends and Effects in the Eastern U. S. GAO, 2009.
Print.
Houston, William. and Griffiths, Robin. Water. Petersfieled: Harriman House Ltd, 2010. Print.
Lew, Kristi. Acids and Bases. New York: InfoBase Publishing, 2009. Print.
Likens, Gene E. ed. Biogeochemistry of Inland Waters. Mequon, WI, USA: Elsevier Inc., 2009.
Print.
Appendices
Appendix 1: Strong and Weak Bases
Weak Ammonium base does not dissociate to lose all hydroxide ions.
Strong Sodium hydroxide base dissociates completely to lose all hydrogen ions.
Appendix 2: Neutralization
Acid + Base → Salt + Water
OH−(aq) + H+ (aq) → H2O
HCl (aq) + NaOH (aq) → H2O (l) + NaCl (aq)
Neutralization occurs when acids and bases react to form water. Water is formed when hydroxide ions reacts with hydrogen ions.
In this case, potassium hydroxide will react with hydrochloric acid to form potassium chloride salt and water.
Appendix 3: Ph Scale Ranges
A pH level more than 7 is basic, whilst that less than 7 is acidic. At 7, a substance will be neutral. In this regard, water is neutral at 7, while battery acids will be between 0 and1 and bleach at 12.
Appendix 4: Corrosives
An acidic corrosive of pH <2 A basic corrosive of pH>12
Appendix 5: Properties of Water
Water is a transparent, tasteless and odorless liquid, which freezes at zero degrees Celsius, and as a compound, it constitutes 88.812% oxygen and 11.188% hydrogen.
Water Freezes at 0 Degrees Celsius
Water has a high surface tension
Appendix 6: Acidic Rain
Sulfur dioxide and nitrogen oxide causes acidic rain by reacting with precipitations in the atmosphere.
Appendix 7: Effects of Acidic Rain
Acidic rain can cause charred face
Acidic rain can cause dried forests
Appendix 8: Usable Water in the World
Usable water, which is only 1% of all waters in the world, is found in rivers, lakes and ground in aquifers.
Appendix 9: Waste Water Treatment
Treatment at Industrial Discharge zone
Municipality treatment plant
