Science-molecules and the mind - Essay Example

science-molecules and the mind Question: Many prepared foods and other consumer products contain EDTA (Edetic Acid or Ethylenediaminetetraacetic Acid) as a sequestrant, to remove metal ions. What structural properties make EDTA an excellent chelating (sequestering) agent Answer: Chelation is a chemical combination with a metal in complexes in which the metal is part of a ring. When held inside the complex, the ions have a limited ability to react with other ions. The larger number of ring closures to a metal atom is the more stable the compound.

So, chelating (sequestering) agent is a chemical whose molecular structure can envelop and hold a certain type of ion in a stable and soluble complex. Ethylenediamine Tetraacetic acid (EDTA) is a well-known sequestering agent with the capacity to chelate almost every positive ion in the periodic table. The EDTA molecule can bind to metal ions by forming six bonds (and six rings) to it - two from nitrogen atoms in amino groups and four from oxygen atoms in carboxyl groups. As the number of ring enclosures is very large (six) the formed chelate is very stable.

Obviously, it is the most widely used chelating molecule.An independent EDTA molecule with Six binding sites4 H on carboxylic acid groups 2 lone pairs of electrons on nitrogenEDTA around Metal Ion with the formation of 6 ring like structure in which metal is a part.Q: Name two other common sequestrants used in consumer products. Answer: Other Common sequestrants used in consumer products include:DTPA ACIDNTA ACIDCAS NO.: 67-43-6FORMULA: C14H23N3O10MOL WT.: 393.35CAS NO.:139-13-9FORMULA: C6H9NO6MOL WT.: 191.14Q: Why is it so important to remove metal ions from oil-based foods Answer: Metals contaminate the food by finding their way from the soil and from machinery during harvesting and processing.

Metals such as copper, iron and nickel degrade the quality of food stuffs by catalyzing the oxidation of the fats and oils in the food. Due to this oxidation, the oil becomes rancid. Rancid oils are a major source of free radicals in our diet which can cause cancer, diabetes, Alzheimer's and other diseases associated with them. Hence the metal ions in oil-based foods can cause severe health problems and it is important to remove them from oil-based foods. Sequestering agents can be used to remove these metal ions from oils.

EDTA is commonly added to fatty, oily foods as an antioxidant that prevents metal ions that have entered from metallic food-processing equipment.Q: Why is it important to remove metal ions from soaps and other detergents Answer: Washing the oily spot with plain water is difficult because oil is a hydrocarbon that does not dissolve in water. Oil and water repel each another, so the oil adheres even more strongly to clothing in the presence of water. The addition of soap to water changes the situation; soapy water can dissolve oil from clothing and rinse it away.

Soap is soluble sodium or potassium salts of carboxylic acids. It dissolves in water, forming the sodium and stearate ions. Even though most of the stearate ion is a hydrocarbon chain, it dissolves in water because of the carboxylate group. The carboxylate end is called hydrophilic (water-loving), and the hydrocarbon tail is called hydrophobic (water-fearing). The positively charged cations such as Calcium (Ca2+) and Magnesium(Mg2+) react with stearate anions to form the metal salts precipitate, reducing the oil-dissolving efficiency of the soap.

Other ions, such as iron (Fe2+) and manganese (Mn2+), may also contribute to the hardness of water, but are generally present in much lower concentrations. Hence, Soap is less effective in presence of metal ions. To maintain good soap efficiency, removal of these metal ions is necessary. Sequestering agents can be used for the purpose.Q: Why doesn't the identity or concentration of anions present in water reduce the efficiency of soapAnswer: Soap dissolves in water, forming the sodium and stearate ions.

The long hydrocarbon chains of the stearate anions that dissolve the oils and greases. If water containing dissolved soap is mixed with oil, the hydrocarbon chains strongly attract the oil, while the ionic ends keep the soap dissolved into water. As mentioned above, the cations reduce the efficiency of soap. However, the anions present in water are unable to react to negatively charged stearate anions (like charges repel each other and don't react chemically) and hence their identity or concentration does not reduce the efficiency of the soap.