Category: Physical
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What is the difference between bond enthalpy and bond dissociation enthalpy?
The bond energy term is the energy actually required to break a bond, or rather a mole of these bonds. The fragments that you produce depend on what the actual bond is holding together. There are two terms that are used: 1. Bond enthalpy – this is the average of a bond of a certain…
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How does atomic absorption work?
To understand atomic absorption it is necessary to take a look at some of the concepts involving the nature of light itself. Light is just a form of electromagnetic radiation. The term electromagnetic radiation refers to the propagation of energy through a medium (or a vacuum) in the form of oscillations of an electrical nature with…
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How does the iodine clock reaction work?
The iodine clock reaction times how long it takes for a fixed amount of thiosulphate ions to be used up, i.e. the time taken for the iodide ions to reach a fixed number of moles produced in the reaction between potassium iodide and an oxidising agent (usually hydrogen peroxide, or sodium peroxodisulphate). The system is…
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Which factors contribute to the boiling point of ethanoic acid?
Boiling points are a function of the intermolecular forces. The ethanoic acid dimer has an effective RMM = 120. This means that considerable Van der Waals force would be expected between particles. Compare with a totally non-polar molecule with a similar relative mass such as decane. The boiling point of decane is 174ºC. Were ethanoic…
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Why do we study kinetics of reactions?
Original post: Friday, May 18th, 2007 The study of kinetics is to find out the things that affect how fast reactions occur and then ultimately to explain the actual mechanics of the process (what actually happens and in which order) On the basic level, simply observation shows us that changing the concentration of reactants affects…
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How can enthalpy of formation values be used to calculate reaction enthalpy?
Friday, May 18th, 2007 Think about it this way… the reactants (left hand side) go on to make the products (right hand side) Imagine that this reaction proceeds VIA the elements in their standard states, (according to Hess’s law we can go any way we want providing that we get to the desired products) First…