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Chemistry

Mass and heat transport

Mass transport - diffusion In fluid systems, the position of the particles (atoms, molecules) changes as a result of the temperature movement. If we imagine a particle marked, it looks like this: The dynamics of the diffusion are illustrated by an animation on the following page. The marked particle has traveled a zigzag path as a result of the collisions in the time Δt and has reached the location indicated by the arrow.
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Chemistry

Practical experiment in determining molar mass according to Dumas

Molecular mass determination - carrying out the experiment Prepare the Dumas flask First, the neck of the flask is pulled out into a capillary. To do this, warm the glass over a non-glowing Bunsen burner flame (open air supply on the burner). Grasp the tip of the neck with tweezers and pull, as soon as the glass becomes soft, until there is just an opening in the resulting capillary.
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Chemistry

Battery

The electrolyte of the zinc-mercury battery consists of potassium hydroxide solution with the addition of zinc oxide. Structure Fig. 1 Section through a mercury button cell Anode reaction: Zn → Zn2 ++ 2e − Cathode reaction: HgO + H2O + 2e− → Hg + 2OH − The zinc-mercury primary cell has a high energy density and a long shelf life (5-8 years).
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Chemistry

Atomic absorption spectrometry

Two types of radiation sources are used in atomic absorption spectrometers: line sources and continuum sources. Line sources emit a line spectrum and serve as the source of the measurement light, the absorption of which is measured in the flame and used to determine the analyte.
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Chemistry

Plant genetic engineering

FungicidesFungicides are often neglected when it comes to controlling plant pests, although they have a high role in causing infectious diseases in plants. Fungi are fought with fungicides (from Latin fungus, & 34; mushroom & 34; and caedere, & 34; kill & 34;). There are three types of fungicides: foliar and soil fungicides, both of which have a preventive or infection-fighting effect, as well as dressings.
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Chemistry

Hormones - an introduction

Peptide hormones are made up of amino acids linked together by peptide bonds. Peptide hormones are insoluble in fat and therefore cannot easily penetrate the cell membrane. They bind to specific surface receptors that are only located on the respective target cells at the site of action.
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