Berdasarkan daya hantar listriknya, suatu larutan dapat dibedakan menjadi larutan elektrolit kuat, elektrolit lemah dan non elektrolit. Hal tersebut didasarkan pada derajat ionisasi dari zat yang terlarut didalamnya. Salah satu cara secara kuantitatif untuk mengetahui sifat larutan berdasarkan daya hantar listriknya yaitu dengan mengukur larutan tersebut dengan alat konduktometer. Nila daya hantar listrik yang terukur oleh alat konduktometer merupakan nilai daya hantar ekivelan yang didefiniskan sebagai kemampuan suatu zat terlarut untuk meghantarkan arus listrik pada satu gram berat ekivalen zat terlarut tersebut di antara dua elektroda dengan jarak 1 cm. Definis dari berat ekivalen zat itu sendiri adalah berat molekul zat dibagi dengan jumlah muatan ion positif dan negatifnya. Daya hantar ekivalen pada larutan encer diberi simbol yang nilainya tertentu untuk setiap jenis ion. Konduktometer merupakan alat yang memerlukan prosedur pemakaian khusus karena terkait dengan sensitivitas pengukurannya yang harus selalu dijaga agar tetap mendapatkan hasil pengukuran yang memiliki akurasi tinggi. Berikut ini instruksi kerja dari konduktometer yang perlu diperhatikan. Read more »
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Alat Konduktometer: Alat Pengukur Daya Hantar Listrik Pada Larutan Dalam Kegiatan Penelitian dan Praktikum di Laboratorium
Chemistry Ebook: Recommended Methods of Manure Analysis
Chemistry Ebook: Mass Spectrometry Instrumentation, Interpretation, and Applications
The first part of this book is dedicated to a discussion of mass spectrometry (MS) instrumentation. We start with a list of basic definitions and explanations (Chapter 1). Chapter 2 is devoted to the mass spectrometer and its building blocks. In this chapter we describe in relative detail the most common ion sources, mass analyzers, and detectors. Some of the techniques are not extensively used today, but they are often cited in the MS literature, and are important contributions to the history of MS instrumentation. In Chapter 3 we describe both different fragmentation methods and several typical tandem MS analyzer configurations. Chapter 4 is somewhat of an outsider. Separation methods is certainly too vast a topic to do full justice in less than twenty pages. However, some separation methods are used in such close alliance with MS that the two techniques are always referred to as one combined analytical tool, for example, GC-MS and LC-MS. In effect, it is almost impossible to study the MS literature without coming across at least one separation method. Our main goal with Chapter 4 is, therefore, to facilitate an introduction to the MS literature for the reader by providing a short summary of the basic principles of some of the most common separation methods that have been used in conjunction with mass spectrometry.
Ebook Of Analysis Methode: Handbook Of International Center for Agricultural Research in the Dry Areas (ICARDA)
(Picture from http://www.icarda.org)
The idea that one could test or analyze a soil and obtain some information about its properties especially its acidity or alkalinity and its nutrient status is long established, and can be traced back to the beginning of scientific inquiry about the nature of soil. Analysis of plant to reflect fertility status of the soil in which it grew is more recent, although visual crop observations are as old as the ancient Greeks, if not older. In the last few decades, spurred on by commercialization of agriculture and the demands for increased output from limited and even diminishing land resources, both soil and plant analysis procedures have been developed, and are still evolving.
With the advent of chemical fertilizers, the need to know nutrient status of a soil in order to use these expensive and limited inputs more effectively became all the more crucial. However, if soil testing is to be an effective means of evaluating fertility status of soils, correct methodology is absolutely essential. A soil or a field may be assessed for its capability of providing a crop with essential nutrients in several ways:
- Field Plot Fertilizer Trials;
- Greenhouse Pot Experiments;
- Crop Deficiency Symptoms;
- Plant Analysis;
- Rapid Tissue or Sap Analysis;
- Biological Tests, such as Growing Microorganisms; and
- Soil Testing prior to Cropping
