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Safe oxygen evolution method
There are occasional accidents in oxygen evolution experiments. The cause is that the wrong concentration of hydrogen peroxide solution or the use of powdered manganese dioxide increases the surface area and causes a violent reaction. There is also such a generation method, so why not try it?
Experiment 1: Safe oxygen evolution method
Sodium percarbonate is very easy to do, so I will introduce it.
Prepare an oxygen-based bleach (sodium percarbonate). Weigh about 5g, put it in a small Erlenmeyer flask, and pour hot water. It is better to heat the water, and pour 80 to 90 hot water. The reaction formula is as follows. 2Na2CO3 ・ 3H2O2 → 2Na2CO3 + 3H2O2: 2H2O2 → 2H2O + O2
If it does not occur very often, shake the flask or soak it in hot water. When all 5g of substances react, about 0.6L of oxygen is generated. Since the test tube is 40 ml, I think it is enough for the group experiment.
Sodium carbonate becomes Na2CO3 → 2Na + + CO32−: CO32− + H2O → HCO3- + OH− and becomes an alkaline liquid. The waste liquid is the same as a strong detergent, so rinse it with a large amount of water. You can buy oxygen bleach for about 500 yen for 700g.
Experiment 2: Hydrogen generation method
If you have all the chemicals, you can use metal in hydrochloric acid. I will write about the case where there is nothing. Electrolysis will be the easiest. Baking soda is sold even if the chemicals are not available. Baking soda is heated to sodium carbonate and then dissolved in water for electrolysis.
Turn off the charging cord for your smartphone. Attach the clip and connect it to your PC or power supply. Since it is a 5V power supply, it is a voltage that is just right for electrolysis. I also make my own electrolyzer. Sodium carbonate takes a long time to electrolyze, but if there is, I would like to use sodium hydroxide.
Experiment 3: Is carbon dioxide heavier than air? Is it true?
As shown in the photo on the left, carbon dioxide is generated when carbonate is mixed with acid. (This time, we will use vinegar as the acid and multiple layers as the carbonate, assuming that we will use familiar ones.) When this generated gas is poured over the candle, the candle flame will disappear. This is because carbon dioxide is heavier than air and has the property of extinguishing fire.
Then, as shown in the photo on the left, put two candles of different lengths in the beaker and light them. Considering the nature of carbon dioxide, it is heavier than air and has the property of extinguishing fire, so it is short to extinguish first. I think it's the one ... But it's the long one that always disappears first no matter how many times it is done. ・ ・ ・ ・ ・ ・ ・ ・
This is because the carbon dioxide produced by the candles is warm and light. Occasionally, how about taking a break in an experiment like this trick?
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