Index & Contents – July 2012 to July 2015
To go to a post in the contents list below, click on the relevant month in the Archives list on the right hand side of the page.
A holiday quiz where nearly all of the answers are Al (aluminium) or Pt (platinum).
A .gif animation is shown of an experiment where aluminium and platinum foils were introduced into a blue Bunsen burner flame side by side.
Rust on a melon
We showed numerous pictures and .gif animations for some oxidation and reduction reactions involving iron. In summary the reactions were:
1. Rusting of iron nails, including a .gif animation of nails in an experiment lasting three and a half weeks investigating the factors necessary for rust formation.
2. Burning sparklers, including a .gif animation.
3. Speeding up the burning of iron wool by whirling it around on the end of a length of string (.gif animation).
4. A thermit reaction carried out at night over a water melon, including a .gif animation.
Balls of fire
We described a rapid, small scale method for making nitrocellulose without producing large amounts of waste. We experimented with using potassium carbonate, lithium carbonate, limewater (calcium hydroxide) and barium carbonate in place of sodium hydrogencarbonate to neutralise the acid reaction mixture. As a result, nitrocelluloses were produced which gave different burning characteristics and flame colours.
Ten .gif animations are shown, one each at normal speed and one in slow motion for sodium, potassium, lithium, barium and calcium impregnated nitrocelluloses.
Food colour frenzy
We repeated the dancing droplets of food colour reported by Nate Cira, Adrien Benusiglio and Manu Prakash. Five .gif animations are shown of the droplets moving on microscope slides. We found that red food colour was best at pushing around all the other colours. We also posted a movie ‘Red Peril’ Food Dye which can be viewed here: https://www.youtube.com/watch?v=IKY-Zqa7R10
More fun with luminol
We describe a novel way of showcasing the classic luminol chemiluminescent reaction by carrying it out in a dense layer of sucrose solution at the bottom of a measuring cylinder, which also contained hydrogen peroxide. A second less dense layer of sucrose is layered on top of this mixture and serves as a barrier to a third top layer which contained iron (III) chloride and copper (II) sufate solutions. The reaction was started by dropping a small piece of lead metal dipped in manganese dioxide powder into the measuring cylinder.
The oxygen bubbles produced by the decomposition of the hydrogen peroxide rise up the measuring cylinder and are surrounded by blue lighht from the luminol reaction.
A movie of the reaction can be viewed here: https://www.youtube.com/watch?v=mt8EX4pZuJU&feature=youtu.be
Numerous pictures and seven .gif animations of Bicarbonate Rockets, which are often made at school. These rockets are constructed from plastic bottles and fuelled with a reaction mixture of vinegar and sodium bicarbonate. The two reactants produce carbon dioxide gas, but it is the force of the liquid reaction mixture blown out of the bottom of the bottle by the carbon dioxide which provides most of the upward lift. The most critical design feature for our rockets was finding a plastic bottle with a neck of just the right size diameter to match our medium sized rubber bungs.
Numerous pictures and four .gif animations of Propane Rockets made using a plastic bottle and a mixture of oxygen and bottled gas. These can be used to illustrate stoichiometry and balanced chemical equations when studying chemistry at school.
Details of the .gif animations are as follows; three (normal speed) .gif animations showing:
1. Complete combustion of the fuel (enough oxygen) and a very fast rocket.
2. Incomplete combustion (not enough oxygen) and a slow moving rocket.
3. Incomplete combustion (not enough oxygen) and failure to launch.
The fourth .gif animation is a slow motion animation constructed from a high speed movie shot at 1000 frames per second. It shows the fuel burning down the bottle as the rocket takes off.
Match head rockets
Numerous pictures and four .gif animations on how we make our Match Head Rockets in Chemistry Club.
Also, three pictures and a .gif animation showing the products of the two experiments featured in the November 2014 post.
Two exothermic chemical reactions commonly carried out at school
1. Iron and sulfur
A .gif animation and other pictures are shown for the reaction which takes place when a mixture of iron filings and sulfur are heated together in a test-tube. Iron sulfide is produced.
2. Copper (II) oxide and carbon
A .gif animation and other pictures are shown for the reaction which takes place when a mixture of copper (II) oxide and carbon are heated together in a test-tube. A thermal reduction takes place leading to the formation of copper metal.
Fun with luminol
Variations on the classic demonstration reaction utilising the chemiluminescence of luminol.
In one experiment the luminol reaction mixture was poured into a Petri dish and drops of iron (III) chloride and copper (II) sufate solutions were dropped into it using pipettes. Flashes of light were produced around the droplets as they fell into the reaction mixture.
In a second experiment the luminol reaction mixture was again poured into a Petri dish, drops of iron (III) chloride and copper (II) sufate were added and then the mixture was electrolysed using carbon electrodes and a 9 volt power supply.
A .gif animation is shown for each of these two experiments.
Demonstrating the bleaching effect of hydrogen peroxide solution using strawberries and the effect of temperature on the rate of these reactions.
A .gif animation of a frozen strawberry warming up to room temperature next to a strawberry already at room temperature, (the former goes all squashy).
A .gif animation of a strawberry dropped into 6 vol hydrogen peroxide in a small beaker.
A .gif animation of a frozen strawberry and a room temperature strawberry dropped into beakers of hydrogen peroxide side by side.
On the reactivity series of metals studied at GCSE level in chemistry and reactions of magnesium, zinc, iron and copper with 2M hydrochloric acid.
Includes a .gif animation showing the four metals reacting with 2M hydrochloric acid for approximately a minute, then a second .gif animation showing the reaction of an iron nail and a piece of copper foil with 2M hydrochloric acid over a period of a week.
What does the word ‘salt’ mean?
On the two meanings of the word salt in chemistry at school.
A .gif animation showing the build up of a 3D digital image modelling the cubic shaped ionic lattice of sodium chloride.
A celebration of IYCR, The International Year of Crystallography 2014
A lot of images of crystals of ionic compounds encountered by students at school, including thirteen .gif animations of crystals growing, as seen under a microscope.
The crystals shown in order of appearance are:
Copper (II) sulfate
The colours seen in web images for flame tests vary.
There are .gif animations for lithium, sodium, potassium and calcium flame tests.
Alkali metals in water
A .gif animation of lithium, sodium and potassium metals added to a small bowl of water at the same time from a spatula.
Three .gif animations, one each for lithium, sodium and potassium metals, added to a small bowl of water individually.
A .gif animation showing lithium, then sodium, then potassium metals being added to a large trough of water sequentially.
When a mixture of sucrose (4 parts) and sodium bicarbonate (1 part) is doused with ethanol and set light to, trailing ‘snakes’ of dark grey ash emerge from the flames.
Includes a .gif animation of the experiment and another illustrating the artistic qualities of the ‘snakes’ produced.
The chromatography of chlorophyll
Thin layer silica chromatography of a chlorophyll containing extract from grass. We used a 70:30 mixture of diethyl ether : petroleum ether (bp 60-80) as the eluting solvent. Includes numerous images of the procedure and a .gif animation of the elution of a TLC plate and pigment separation.
On the u.v. fluorescence of quinine (from tonic water) and chlorophyll (from spinach). The .gif animations show the following subjects illuminated by alternating u.v. light and fluorescent light.
A .gif animation of jelly made with and without the addition of tonic water in plastic cups.
A .gif animation showing the red colour of spinach juice.
A .gif animation showing a ‘spooky vampire smiley face’ fashioned from jelly made with tonic water and spinach juice.
Snow from brine
Making ‘snow scenes’ from cardboard soaked in saturated sodium chloride solution spiked with a few drops of potassium hexacyanoferrate (II)
Modelling a sodium chloride crystal
A .gif animation showing a rotating model of the sodium chloride crystal lattice, made from brightly coloured modelling clay.
Rudolf the red-nosed boiling tube
A Christmas themed Santa’s challenge experiment, involving the reaction of sodium hydrogencarbonate and calcium carbonate with hydrochloric acid.
.gif animations of B/Z reactions in a beaker (one animation) and in Petri dishes (five animations)
High speed photography and .gif animation of the explosive reaction between hydrogen and oxygen bubbles and a high speed .gif animation of the hydrogen “pop” test.
Halloween Chemistry 2
Pictures showing the use of fluorescent inks extracted from highlighter pens in a Halloween themed display under u.v. light.
Hydrogen chloride and ammonia diffusion experiment
A .gif animation showing the diffusion of hydrogen chloride and ammonia gases which react to form a ‘white smoke’ of ammonium chloride in a glass tube. In the experiment we used a temperature probe to show the exothermic nature of the reaction.
A .gif animation showing the explosion produced when a mixture of hydrogen and oxygen bubbles are lit with a burning wooden splint.
A .gif animation using Lewis diagrams to illustrate the balanced equation for the reaction between hydrogen and fluorine.
A .gif animation showing the diffusion of hydrogen chloride and ammonia gases in a glass tube and reacting to produce ‘white smoke’ of solid ammonium chloride.
When hydrogen met fluorine, including a .gif animation showing bond formation in a molecule of hydrogen fluoride.
Explaining the results seen in the halogen/halide displacement reactions June 2013 .gif animation. Chlorine displaces bromide ions and iodide ions from solution. Bromine displaces iodide ions from solution.
Halogen/halide displacement reactions in aqueous solution
A .gif animation showing iodine, bromine and chlorine added to NaCl, NaBr and KI.
Two .gif animations, one illustrating the formula of calcium fluoride (fluorite) and a second showing the fluorescence of fluorite under u.v. light.
Testing for chlorine
A .gif animation of the bleaching effect of chlorine on some orange flowers.
A .gif animation showing chlorine gas bleaching red and blue litmus paper.
Testing for carbon dioxide
A .gif animation of an experiment illustrating the thermal decomposition of copper (II) carbonate and testing the carbon dioxide gas produced by bubbling it through limewater
A .gif animation showing a large carbon dioxide bubble bursting and extinguishing six burning candles placed around it.
Testing for hydrogen and oxygen gases
Three .gif animations of test-tube reactions; testing for hydrogen gas with a burning wooden splint, testing for hydrogen with a hot piece of platinum foil and testing for oxygen with a glowing wooden splint.
Testing for water using cobalt (II) chloride
A .gif animation of cobalt chloride paper used in testing for water; blue when wet (hydrated), pink when dry (dehydrated). Cobalt (II) chloride is also sometimes used as an indicator in the silica gel drying agent used in desiccators, but it is toxic.
Testing for water using copper (II) sulfate
A .gif animation of a simple dehydration experiment heating hydrated copper (II) sulfate in a test-tube with a Bunsen burner and then adding water to it.
The colours of copper (II) chloride, copper (II) nitrate and copper (II) sulfate crystals in pictures, a laboratory desiccator and its effect on hydrated aluminium sulfate over time.
Coloured crystals to illustrate the “Halloween Chemistry” poem, fake blood, green copper (II) chloride in a Santa illustration, wet lithium chloride crystals and a silver bearded wolf’s head
The shapes of large NaCl, NaBr, NaI crystals in pictures
“Halloween Chemistry” poem, KCl, KBr, KI crystals in one picture
The Periodic Table, lithium fluoride and sodium chloride
Ionic bonding and the sodium chloride lattice