Category: Inorganic
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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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What is the molecular formula of sulfur?
The formula of the elements is best left to the simplest possible form, except in the case of the gases and the halogens, that are shown as diatomic molecules by tradition. The remaining elements are simply expressed as a single atoms, although it must be emphasised that elements, or rather the atoms of elements, do not…
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How does copper react with nitric acid?
Copper is an unreactive metal and doesn’t react in normal circumstances with dilute acids. However it does react with nitric acid. Why is this? Nitric acid is an oxidising agent and the reaction is not the usual acid + metal reaction. The products are oxides of nitrogen instead of hydrogen. The actual nitrogen oxide formed…
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Why can hydrogen peroxide act as both an oxidising agent and a reducing agent?
Hydrogen peroxide has the ability to gain or lose electrons, as its oxygen atoms are in the -1 oxidation state. By gaining electrons they can go to the -2 oxidation state, and by losing electrons they can go to the zero oxidation state (the element) When someting acts as an oxidising agent is gains electrons…
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What is the structure of sulfur(IV) oxide?
SO2 seems to be a little confusing as there are several different descriptions circulating. Some books claim that it has an expanded octet, although there is no real evidence to support this. It can be simply described without octet expansion in that there are only 8 electrons around the central sulfur atom. On a simplistic…
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How is the volume measurement of hydrogen peroxide related to its molarity?
May 21st, 2007 Hydrogen peroxide decomposes according to the equation: 2H2O2 –> 2H2O + O2 If you start with 100 volume H2O2 then 1 dm3 of solution will release 100 dm3 oxygen (at RTP) This means that 1 litre of H2O2 solution releases 100/24 moles of oxygen and as 2 moles of H2O2 decompose to…
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What actually happens when a liquid boils?
May 21st, 2007 All liquids contain particles in which the energy distribution is governed by the laws of statistics. This energy distribution may be plotted as a curve, called the Maxwell Boltzmann graph that shows some particles with very little energy, some with large amounts of energy and the bulk of the particles with energy…
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How does electrolysis work?
May 26th, 2007 There are several misconceptions about electrolysis, such as the idea that electricity flows across the electrolysis cell. The conditions required for electrolysis are an electrolyte with ions that are free to move. They may be in solution or in the form of a molten salt. There must then be an electrical potential…
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What does oxidation state actually mean?
May 31st, 2007 The term oxidation state is a convenient way of describing the effective condition of an atom in a compound in terms of the charge that it would have if it were ionic. It is not intended to suggest that atoms have a specific charge, but it is a useful way of describing…
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Why do allotropes have different colours?
May 31st, 2007 Colour is caused by selective absorption of certain wavelengths and reflection of the rest. The most familiar example would be that of phosphorus, which has three allotropes each of which have a different colour; white, red, and black, and several variations within these three basic forms. The structure of the red form…