Screening and identification of rhizobacteria isolated from heavy metal contaminated soils INTRODUCTION As a result of human activities such as mining‚ agriculture and industrial activity‚ heavy metal pollution has become one of the most serious environmental problems today. Elevated levels of heavy metals not only decrease soil microbial activity and crop production‚ but also threaten human health through the food chain. Soil microorganisms can degrade organic contaminants‚ while metals need immobilization
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Reactivity of Halide Ions Purpose: There are four halide salts used in this experiment that are found in the human body. Sodium fluoride is poisonous‚ but has been traced to be beneficial to humans in the prevention of tooth decay. Sodium chloride is added to many of our foods to increase flavor. Sodium chloride is important for many life processes‚ but too much intake is linked to high blood pressure. Sodium bromide is distributed throughout body tissues. Sodium iodine controls cell growth. The
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EXTRACTION OF METALS SUMMARY Most metals exist in compounds in rocks in the Earth’s crust. Many of these ores contain oxides or sulphides of the metals. The compounds need to be reduced to produce the metals as elements. Metals are very useful to us because of their special properties. Reduction means removal of oxygen or gain of electrons. Carbon is a good chemical reducing agent because it readily combines with oxygen‚ but it is only useful for the metals below it in the Reactivity
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Chemical Prperties of Metals Most metals are chemically reactive‚ reacting with oxygen in the air to form oxides over changing timescales (for example iron rusts over years and potassium burns in seconds). The alkali metals react quickest followed by the alkaline earth metals‚ found in the leftmost two groups of the periodic table. Examples: 4Na + O2 → 2Na2O (sodium oxide) 2Ca + O2 → 2CaO (calcium oxide) 4Al + 3O2 → 2Al2O3 (aluminium oxide) The transition metals take much longer to
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Corrosion of Metals Introduction Have you ever had a bike that went rusty‚ figure 1? If the paint is scratched and the rust allowed to spread‚ it is very difficult to repair the frame so it looks as good as new again. Rusting costs us millions of pounds each year‚ either through replacing things or through trying to prevent it happening in the first place. Figure 1: Bike rusting. In this booklet you learn about rusting and ways of stopping it‚ followed by a look at another metal‚ aluminium that
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The brass alloy we are experimenting on is called Muntz Metal. Muntz metal is 60% copper‚ 40% zinc and a hint of copper [http://en.wikipedia.org/wiki/Muntz_metal] (accessed 4/10/12). Muntz metal was developed as an alternative to expensive‚ heavy copper. It is comprised of about 60% copper and about 40% zinc‚ with a small amount of iron. The finished product actually is considered a form of brass‚ but it has maintained its name of Muntz metal. [http://www.wisegeek.com/what-is-muntz-metal.htm] (Accessed
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Consitution of 1962 Background On 7 Oct 1958 the military assumed power in Pakistan under the leadership of general Ayub Khan who was the Commander in Chief at that time. The military abrogated the Constitution and the federal and provincial cabinets were abolished. The national and provincial assemblies were also abolished and martial law was imposed in Pakistan.Ayub Khan became the chief martial law administrator and in this way the 1st military govt came into existence in Pakistan. During
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B.Sc. (H) Computer Science 3-YEAR FULL TIME PROGRAMME RULES‚ REGULATIONS AND COURSES CONTENTS DEPARTMENT OF COMPUTER SCIENCE FACULTY OF MATHEMATICAL SCIENCES UNIVERSITY OF DELHI DELHI – 110007 2010 Semester Systems at the undergraduate level Course of Study: B.Sc.(H) Computer Semester – I CSHT-101 Programming Fundamentals CSHT-102 Discrete Structures Digital Electronics Calculus and Matrices CSHT-203 Data Structures Semester – II CSHT-204 computer Systems Architecture English Calculus
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MATERIALS : METALS AND NON-METALS Y Iron Coal ou are familiar with a number of materials like iron‚ aluminium‚ copper‚ etc. Some materials have been given in Table 4.1. Table 4.1 : Appearance and Hardness of materials Object /Material Appearance Hardness (Shiny/Dull) (Very hard/ Not very hard) similar change if we try to beat a wood log ? Let us find out. Activity 4.1 Take a small iron nail‚ a coal piece‚ a piece of thick aluminium wire and a pencil lead. Beat the iron nail with
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Identification of Metallic Ions Peter Jeschofnig‚ Ph.D. Version 42-0160-00-01 Lab RepoRt assistant This document is not meant to be a substitute for a formal laboratory report. The Lab Report Assistant is simply a summary of the experiment’s questions‚ diagrams if needed‚ and data tables that should be addressed in a formal lab report. The intent is to facilitate students’ writing of lab reports by providing this information in an editable file which can be sent to an instructor. obseRvations
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