Whenever there are a burn and sodium and air come in contact it gives yellow sodium peroxide. Whenever sodium metal is kept open it vigorously reacts with oxygen and the moisture which is in the air that can catch fire.
Sodium also has quick oxidation and that is the reason they are highly reactive. They can easily cause an explosion if come in contact with atmospheric oxygen in the air. The first time I do the demonstration, I prefer not to add phenolphthalein, so that there will be more scope for inquiry. When I do add it, I add it to all the water before placing it in the cylinder, so that on reaction the colour change is associated with the reaction in this video this is not the case.
The experiment can also be carried out quantitatively by removing the oil from the piece of sodium with petrol ether. The dry sodium can be rapidly weighed, then re-immersed in oil. The volume of hydrogen released is measured. Three pieces of Na were used with a total mass 0. Volume of hydrogen released — using a mL cylinder as I wanted greater precision — was mL. This way I obviated the need to measure temperature and pressure, and to take into account the vapour pressure of water.
I just had to unscrew the burner head above the tap and attach a flexible tube to the outlet and bubble gas into the same inverted measuring cylinder. Mass of gas giving mL was measured as 0. Hence mL corresponds to 0. In this reaction, increase in temperature is predicted and therefore affects the volume of the gas collected. This temperature effect was considered negligible. This is an additional opportunity for inquiry. Have students predict the temperature increase and determine the effect on the volume of hydrogen.
If 2 moles Na release We know that 4. Therefore, there is enough heat to raise g of water by about 8. It can be assumed that most of the heat released in the reaction is absorbed by the water, which is a much better conductor than hydrogen gas — not to mention that the reaction takes place with the water.
It should be noted that no noticeable temperature change was felt to the hand. Of course the initial temperature of the water near the reacting sodium is higher, but the heat will be rapidly dissipated to the rest of the water — given there is much more than g. Here is the Safety Kit that I recommend. Also read: What Makes Something Flammable? Sodium, which has a chemical symbol of Na derived from the Latin word natrium , is a very soft metal famous for its incredible level of reactivity.
Also read: Is Calcium Flammable? Sodium burns in the air and has a typical ignition point of degrees Celsius or degrees Fahrenheit. This means that sodium is relatively flammable and can catch fire at moderate temperatures.
Care should be used with sodium and fire. However, this is not the whole story when it comes to sodium and you can, in fact, trigger a chemical reaction that leads to fire at much lower temperatures with pure sodium. Also read: Is Lead Flammable? Will it Burn? In our school chemistry lessons, our teachers did not take a match to sodium to get it to burn.
Sodium reacts violently with water in an exothermic reaction which releases a lot of heat as fire. And if you put enough sodium in the water, it will release large amounts of hydrogen, which could burn down a building. Also read: Is Sulfur Flammable? Also read: Is Iodine Flammable? It is this reaction that also means that should you ever have to handle sodium; you need to wear gloves while doing so.
It is also worth noting that sodium hydroxide is a caustic substance and if you breathe in fumes of it, it can damage your lungs. Also read: Is Potassium Flammable? Violent Reactivity.
0コメント