Displacement Reactions

We did lots of displacement tests. Photos to come for the copper sulphate etc, but in the meantime these were good:

http://lavenderpondnotes.tumblr.com/post/91360405006/spotting-tile-with-samples-of-metal-immersed-in

http://lavenderpondnotes.tumblr.com/post/102827155091/reaction-of-magnesium-with-copper-oxide-this

http://lavenderpondnotes.tumblr.com/post/102828127091/reaction-of-magnesium-with-copper-ii-oxide-the

Oxides and Carbonates

We did several practical activities from the Royal Society of Chemistry’s Classic Chemistry Experiments collection today, to illustrate important chemical reactions. We often hear the terms ‘carbonate’ and 'oxide’ so today we found out a bit more about what these mean.  A carbonate of a metal has a CO3 attached to it, while an oxide has oxygen attached to it.

The Combustion of Iron Wool

We made a seesaw balance by perching strips of wood on triangular blocks.  We put plasticine at one end and iron wool at the other, arranged so that the plasticine just outweighed the iron wool.  We set light to the iron wool and waited for something interesting to happen.  It was quite difficult to set alight and, when we did set it alight, most of us didn’t get a conclusive result.  We tried again, using a longer balance beam - a metal metre rule.  This worked brilliantly and we saw that,, even though sparks were coming off the burning iron wool, it still tipped the balance away from the plasticine and moved down.  This showed that the iron wool became heavier as it burned.

The RSC description and instructions for this : The Combusion of Iron Wool

The Change in Mass when Magnesium Burns

A short piece of magnesium ribbon was cleaned and placed in a ceramic crucible with a lid. The crucible was weighed and the mass noted. The crucible was placed on a pipe clay triangle, on top of a tripod, over a bunsen burner.  We heated it strongly and lifted the lid to let more air in.  We could see a bright light coming from inside the crucible.  After it had all cooled down, we weighed it again and it weighed slightly more than it had originally. The magnesium ribbon had changed into white powder. This was magnesium oxide, and the crucible weighed more because the additional oxygen which had combined with the magnesium had increased the overall mass.

Further reading and how-to: RSC Change in mass when magnesium burns

The Effect of Heat on Metal Carbonates

We heated two different chemicals - sodium carbonate, and copper carbonate.  Each was put into a separate test tube, then we put a bung in which had a hole and a right-angled glass delivery tube.  Of particular note: Alison and Angie made these customised delivery tubes by heating plain glass tubing in a strong flame! The gas produced was bubbled through limewater, and for both chemicals the gas turned the limewater milky.  This showed it was carbon dioxide.

Further info and instructions: RSC Effect of Heat on Metal Carbonates

http://lavenderpondnotes.tumblr.com/post/102820024151/oxides-and-carbonates-we-did-several-practical

http://lavenderpondnotes.tumblr.com/post/102826621951/combustion-of-iron-wool-our-triumph-as-the-iron