The first talk was delivered by our very own Chemistry Teacher, Mr. Chen (A graduate from the Chemistry department of Nanjing Normal University. His main research is in the field of physical chemistry and carbo nano-materials.)
1.“彩虹杯” “Spectrum Beakers”
Through the use of colour, a pH indicator can tell us the pH value of a solution. With Mr. Chen’s guidance, one of our students used the indicator with beakers filled with different solutions. The solutions showed the whole spectrum of colour demonstrating differing pH values.
A hydrochloric acid solution of phenolphthalein is usually colourless. However when adding sodium hydroxide, the solution all of a sudden turns a bright red before immediately disappearing again.
By mixing foaming solution with potassium iodide and a hydrogen peroxide solution, a huge flurry of bubbles with fly out and the beaker will overflow.
By placing black manganese dioxide in a hydrogen peroxide solution, a large amount of energy will be released, causing the solution to reach boiling point in the blink of an eye. This then
transforms into large quantities of steam.
When sodium carbonate meets a phenolphthalein indicator, the solution will turn a bright pink, almost resembling a cocktail! When hydrochloric acid is added, a large quantity of bubbles are produced, the colour toning down to look like a glass of Sprite instead.
6.银镜反应 Silver Mirror Reaction
When a solution of silver nitrate, ammonia, sodium hydroxide and glucose is mixed together, it will quickly start to shake. Then after a small period of time, a layer of glistening silver will appear around the beaker.