Chemical Health Hazards

Ions Ions are charged substances that have formed through the gain or loss of electrons. Cations form from the loss of electrons and have a positive charge while anions form through the gain of electrons and have a negative charge. Cation Formation Cations are the positive ions formed by the loss of one or more electrons. The most commonly formed cations of the representative elements are those that involve the loss of all of the valence electrons. Consider the alkali metal sodium (Na) . It has one valence electron in the n=3 energy level. Upon losing that electron, the sodiu ion now has an octet of electrons from the second energy level and a charge of 1+ . The electron arrangement of the sodium ion is now the same as that of the noble gas neon. Consider a similar process with magnesium and aluminum. In this case, the magnesium atom loses its two valence electrons in order to achieve the same arrangement as the noble gas neon and a charge of 2+ . The aluminum atom loses its three valence electrons to have the same electron arrangement as neon and a charge of 3+ . For representative elements under typical conditions, three electrons is usually the maximum number that will be los. Representative elements will not lose electrons beyond their valence because they would have to "break" the octet of the previous energy level which provides stability to the ion. Anions Anions are the negative ions formed from the gain of one or more electrons. When nonmetal atoms gain elections, they often do so until their outermost principal energy level achieves an octet. For fluorine, which has an electron arrangement of (2, 7), it only needs to gain one electron to have the same electron arrangement as neon. Forming an octet (eight electrons in the outer shell) provides stability to the atom. Fluorine will gain one electron and have a charge of 1− . The electron arrangement of the fluoride ion (2, 8) will also change to reflect the gain of an electron. Oxygen has an electron arrangement of (2, 6) and needs to gain two electrons to fill the n=2 energy level and achieve an octet of electrons in the outermost shell. The oxide ion will have a charge of 2− as a result of gaining two electrons. Under typical conditions, three electrons is the maximum that will be gained in the formation of anions. Subatomic Particles in an Ion Since ions form from the gain or loss of electrons, we can also look at the number of subatomic particles (protons, neutrons, and electrons) found in an ion. Remember that the number of protons determines the identity of the element and will not change in a chemical process. Example 2.5.1 How many protons, neutrons, and electrons in a single oxide (O2−) ion? Solution Oxygen has the atomic number 8 so both the atom and the ion will have 8 protons. The average atomic mass of oxygen is 16. Therefore, there will be 8 neutrons (atomic mass−atomic number=neutrons) . A neutral oxygen atom would have 8 electrons. However, the anion has gained two electrons so O2− has 10 electrons. We can also use information about the subatomic particles to determine the identity of an ion. Example 2.5.2 An ion with a 2+ charge has 18 electrons. Determine the identity of the ion. Solution If an ion has a 2+ charge then it must have lost electrons to form the cation. If the ion has 18 electrons and the atom lost 2 to form the ion, then the neutral atom contained 20 electrons. Since it was neutral, it must also have had 20 protons. Therefore the element is calcium. Polyatomic Ions A polyatomic ion is an ion composed of two or more atoms that have a charge as a group (poly = many). The ammonium ion (see figure below) consists of one nitrogen atom and four hydrogen atoms. Together, they comprise a single ion with a 1+ charge and a formula of NH+4 . The hydroxide ion (see figure below) contains one hydrogen atom and one oxygen atom with an overall charge of 1− . The carbonate ion (see figure below) consists of one carbon atom and three oxygen atoms and carries an overall charge of 2− . The formula of the carbonate ion is CO2−3 . The atoms of a polyatomic ion are tightly bonded together and so the entire ion behaves as a single unit. The figures below show several examples. Soult Screenshot 2-2-1.png Figure 2.5.1 : The ammonium ion (NH+4) is a nitrogen atom (blue) bonded to four hydrogen atoms (white). Soult Screenshot 2-2-2.png Figure 2.5.2 : The hydroxide ion (OH−) is an oxygen atom (red) bonded to a hydrogen atom. Soult Screenshot 2-2-3.png Figure 2.5.3 : The carbonate ion (CO2−3) is a carbon atom (black) bonded to three oxygen atoms. The table below lists a number of polyatomic ions by name and by structure. The heading for each column indicates the charge on the polyatomic ions in that group. Note that the vast majority of the ions listed are anions - there are very few polyatomic cations. 1− 2− 3− 1+ Table 2.5.1 : Common Polyatomic Ions acetate, CH3COO− carbonate, CO2−3 arsenate, AsO3−3 ammonium, NH+4 bromate, BrO−3 chromate, CrO2−4 phosphite, PO3−3 chlorate, ClO−3 dichromate, Cr2O2−7 phosphate, PO3−4 chlorite, ClO−2 hydrogen phosphate, HPO2−4 cyanide, CN− oxalate, C2O2−4 dihydrogen phosphate, H2PO−4 peroxide, O2−2 hydrogen carbonate, HCO−3 silicate, SiO2−3 hydrogen sulfate, HSO−4 sulfate, SO2−4 hydrogen sulfide, HS− sulfite, SO2−3 hydroxide, OH− hypochlorite, ClO− nitrate, NO−3 nitrite, NO−2 perchlorate, ClO−4 permanganate, MnO−4 The vast majority of polyatomic ions are anions, many of which end in -ate or -ite. Notice that in some cases such as nitrate (NO−3) and nitrite (NO−2) , there are multiple anions that consist of the same two elements. In these cases, the difference between the ions is the number of oxygen atoms present, while the overall charge is the same. As a class, these are called oxyanions. When there are two oxyanions for a particular element, the one with the greater number of oxygen atoms gets the -ate suffix, while the one with the fewer number of oxygen atoms gets the -ite suffix. The four oxyanions of chlorine are shown below, which also includes the use of the prefixes hypo- and per-. ClO− , hypochlorite ClO−2 , chlorite ClO−3 , chlorate ClO−4 , perchlorate Not your usual ion Soult Screenshot 2-2-4.png "Drink you milk. It's good for your bones." We're told this from early childhood, and with good reason. Milk contains a good supply of calcium, part of the structure of bone. However, there are two other ionic components of hydroxyapatite, the mineral component. Phosphate ion and hydroxide ion make up the remainder of the inorganic material in bone. News You Can Use Bone is a very complex structure. It is composed of protein (mainly collagen), hydroxyapatite (a calcium-phosphate-hydroxide mixture), some other minerals, and contains 10 - 20% water. The calcium/phosphate ratios are not stoichiometric, but vary somewhat from one portion of bone to the next. Bones are very strong but will break under enough stress. Regular exercise and proper nutrition help to increase bone strength. Watch a video about bone structure at http://www.youtube.com/watch?v=d9owEvYdouk Nitrate is an anion with a complex bonding structure. Major sources for this ion in drinking water are runoff from fertilizer, septic tank leakage, sewage, and natural deposits. High concentrations of nitrates represent a significant health hazard, especially to infants. The nitrate in the body is converted to nitrite, which then binds to hemoglobin. This binding decreases the ability of hemoglobin to transport oxygen, thus depriving the cells of the O2 needed for proper functioning. Cyanide production is widespread throughout nature. Forest fires will produce significant amounts of cyanide. Many plants contain cyanide, and it is produced by a number of bacteria, algae, and fungi. Cyanide is used industrially in metal finishing, iron and steel mills, and in organic synthesis processes. This material is also an important component for the refining of precious metals. Formation of a complex between cyanide and gold allows extraction of this metal from a mixture.

Sustainable Farming Practices • Cover Crops: Protect soil from erosion and improve soil health. -Precision Agriculture: Uses technology to optimize field-level management regarding crop farming. • Integrated Pest Management (IPM): Combines biological, cultural, physical, and chemical tools to manage pests sustainably.

Peas  Peas are one of the most important vegetables Zimbabweans can grow for export.  They are legumes  Legumes fix Nitrogen  IMPORTANCE OF PEAS  Peas have a lot of health benefits for human consumption.  They can be eaten raw or added to a variety of dishes  Peas have vitamins and antioxidants.  They are good for heart performance.  They are good for dealing with high blood pressure.  They have a very high protein content VARIETIES  Some of the common varieties to grow are Snowbird, Sabre, Serge, Alaska, Greenfeast and Recruit  Varieties are also called cultivars FAVOURABLE CLIMATE  Peas prefer cold conditions to grow well.  Temperatures of 22 degrees or below (starting at 13 degrees Celsius) are the best for peas farming.  The best temperature is 22 degrees Celsius.  Extremely hot temperatures will lead to lack of growth or hard pods. SOIL REQUIREMENTS  Soil should be fertile.  The soil should have good drainage.  Soil pH must be in the range of 6 to 7.5.  The best soil type is sandy loam – clay soils can also cut it  The soil should be deep LAND PREPARATION  Land preparation includes the following  Dig or plough to aerate the soil and improve drainage  Harrow to break the clods (big lumps)  Make ridges to keep water within the bed  level the bed to ensure equal water distribution SOWING AND PLANTING  Seeds must be sown about 2 to 3 centimeters into the ground  The germination process takes place within at most 1 week.  When sowing seeds, the in-row spacing should be 5 – 10 centimeters whereas the inter-row spacing should be 25 centimeters. Management Practices  Watering is necessary but does not overdo it – water depending on the state of the pea plants.  Generally, peas do not require lots of water.  WEEDING - Weeding should be done occasionally as informed by the state of the field.  MULCHING – to conserve soil moisture  PEST CONTROL – to protect crops from damage  DISEASE CONTROL – to protect crops from damage  TRELLISING – to support indeterminate varieties PEST, DISEASE AND WEED CONTROL  Aphids, beetles, leaf weevils, nematodes, and leaf miners are some of the common pests to look out for.  Powdery and Downey mildew, fusarium wilt are some of the common diseases to look out for.  As much as you can use chemical methods to deal with pests, diseases and weeds you can still use biological and cultural control methods.  Most of the pests and diseases that affect peas can be dealt with by usingcultural methods like weed control.  getting rid of affected plants and plant debris can control pest and diseases control.

Nutrition Notes Nutrition- study of how your body uses food Process by which body uses nutrients How you look and feel Resist diseases and illness How you perform physically and mentally Nutrients: substances in food your body needs to grow, repair and supply energy to your body cells 6 Classes of Nutrients 1.Carbohydrates: 1 gram= 4 calories 2. Protein: 1 gram- 4 calories 3. Fats: 1 gram= 9 calories 4.Water 5. Vitamins 6. Minerals Calorie: measurement of energy in food Metabolism: Rate at which body burns energy(calories) Hunger: physical drive to eat Appetite: pshycological desire for food What influences your food choices: Foods you like Health Reasons Family and Culture Time & Money Advertising Emotions Friends Social Media: Modeling Nutrients Carbohydrates: your body’s main source of energy sugars/starches in food 45%-65% of diet #1 source of energy Simple: sugars converted to glucose= energy (fruits, dairy, honey, some manufactured foods) Complex: sugars linked together (starches) (grains, bread, pasta, beans, vegetables) Fiber: tough, indigestible carbohydrates Cleans our digestive system Prevents some types of cancer Prevents heart disease (fruits, vegetables, whole grains,nuts) 2. Protein: growth and repair of body tissues Made up of chemicals called “amino acids” Basic building material of all body cells (muscles, bones, skin, internal organs) Secondary source of energy protein(hemoglobin) attaches to oxygen in blood Functions as hormones regulating body functions 10-15% of diet *Body uses 20 Amino Acids found in food ( body produces 11 and 9 must come from diet) Essential amino acids: 9 amino acids body doesn't produce Complete Amino Acids: foods that contain all 9 essential amino acids ( animal products) Incomplete Amino Acids: food products that do not contain all 9 essential amino acids. Fats 15-25% of diet Secondary source of energy Blood clotting Controlling inflammation Maintains healthy skin/hair absorb /transport fat soluble vitamins Regulates body temperature Types of Fat Unsaturated: “good” fat Liquid at room temperature Can help fight heart disease (veg oil, nuts) Saturated: “bad” fat Solid at room temp Clogs arteries Causes strokes, heart attack, diabetes (animal products, meat, dairy) Cholesterol: waxy like fat substance found in meat products HDL: good type of cholesterol Body creates(liver) Creates cell wall, hormones, and vit D LDL: bad cholesterol- found in foods (clogs arteries) 4. Trans Fat: “one of the worst type of fats” Formed by a process called “hydrogenation”: adding Hydrogen molecules to unsaturated fats to make it more solid and resistant to chemical change. Vitamins A vitamin is a chemical compound that is needed in small amounts for the human body to work correctly. Vitamins are classified as either fat soluble (vitamins A, D, E and K) or water soluble (vitamins B and C). This difference between the two groups is very important. It determines how each vitamin acts within the body. The fat soluble vitamins are soluble in lipids (fats). Fat soluble vitamins can be stored in our body Water soluble vitamins must be taken every day Human body produces some amounts of Vitamin D & K

Agriculture Agriculture is the main source of livelihood in every country in the region except Brunei and Singapore. Agricultural employment, however, has been declining. More than two-thirds of the workforces of Cambodia and Laos practice agriculture. As the economies of the ASEAN countries have been restructured toward growth in industry and services, there has been a corresponding decline in the proportion of the gross domestic product (GDP) derived from agriculture, most significantly in Indonesia, Malaysia, and Thailand. Agricultural output in Southeast Asia has increased significantly since 1970. There are wide variations in this growth across the region, with the greatest gains in Malaysia and Thailand and little or no increase in Cambodia, Laos, and Vietnam. Hunger and malnutrition are problems in pockets of even the most developed countries, but they have been especially serious in Cambodia because of crop failures and internal strife. The condition of the rural population everywhere is clearly related to limited access to land, the landless experiencing greater poverty and poorer health. Landlessness is perhaps most serious in the Philippines. The dominant form of agriculture in the region is wet-rice cultivation. Where conditions permit, two crops typically are planted each year. Other food crops such as corn (maize), cassava, and pulses (legumes) frequently are grown in drier areas where there is too little water for a second planting of rice. Rice production requires a reliable water supply. Thailand and the Philippines rely heavily on rain-fed systems, while Indonesia utilizes irrigation to a large extent. Irrigation or some other form of water control is especially critical in the cultivation of the high-yielding varieties (HYVs) of rice that have been introduced since the 1960s. The spread of the so-called Green Revolution—in which HYVs and chemical fertilizers and pesticides are utilized—has brought mixed results. There is little doubt that production has increased because of the higher yields of these hybrid strains and because their more rapid maturation increases the possibility of multiple annual crops. Frequently, however, poorer farmers are not able to take advantage of these strains, because of the high cost of their use. The goal of rice self-sufficiency has been difficult to achieve for most countries. A large variety of cash crops are grown for the local and export markets, both on large commercial estates and by individual growers or smallholders. Tree crops are the most important in terms of value, although the area devoted to them is limited largely to equatorial areas. Rubber and palm oil are significant in Malaysia, Indonesia, and southern Thailand, while coconuts and sugar are important in the Philippines. Other major export crops are cacao, coffee, and spices, while crops grown largely for local and regional consumption include chilies, sweet potatoes, peanuts (groundnuts), and tobacco. The cultivation of opium poppies is important in parts of Myanmar and Thailand. The emphasis on rubber and palm oil production is in response to a considerable (though fluctuating) worldwide demand for these commodities and because of a nearly continuous harvest period that provides year-round employment. Foreign corporations once dominated production, but, as the region’s countries gained independence, much of the production was nationalized. Government ownership continues to predominate, with increasing private ownership. Fishing contributes only a token amount to the GDP of Southeast Asian countries, but it is an important livelihood in certain areas and supplies a significant portion of the local diet. Marine output has gradually expanded with new technologies. The maritime nations of Thailand, Indonesia, Malaysia, and the Philippines all have globally important fishing industries. Shrimp catches are especially in demand in the world economy. Aquaculture has become increasingly important in the region, such species as shrimp, carp, and grouper being raised in excavated ponds.

A ______________ is the smallest military unit, typically consisting of 3-5 soldiers and working closely within a tactical operation. A ______________ consists of 8-12 soldiers and is led by a squad leader. A ______________, typically consisting of 30-50 soldiers, is commanded by a lieutenant and subdivided into smaller squads. The ______________ is a company-level unit of about 100-200 soldiers, typically commanded by a captain. A ______________ is made up of several companies, usually commanded by a lieutenant colonel, and consists of 300-1,000 soldiers. A ______________ typically consists of 3-5 battalions, is commanded by a colonel, and can operate independently in large-scale operations. A ______________ is made up of several brigades and is commanded by a major general, usually numbering 10,000-20,000 soldiers. A ______________ is a larger military formation made up of multiple divisions, commanded by a lieutenant general. The term ______________ refers to units designed for direct engagement with enemy forces, such as infantry, armor, and artillery. ______________ is a branch specializing in close-combat tactics and foot soldiers, serving as the backbone of ground forces. ______________ units provide long-range firepower to support ground forces, using cannons, howitzers, and rocket systems. ______________ are specialized units equipped with tanks and other armored vehicles for breakthrough and exploitation missions. The ______________ is responsible for building infrastructure like bridges, roads, and fortifications in combat and non-combat settings. The ______________ provides protection against nuclear, biological, and chemical weapons on the battlefield. ______________ are elite units trained for unconventional warfare, counter-terrorism, and specialized missions. ______________ are responsible for maintaining law and order within military ranks and ensuring security in both combat zones and bases. ______________ provide medical care to soldiers, ensuring health and emergency treatment in battlefield conditions.

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