As you know, substances can be in various states of aggregation, such as: solid, liquid and gaseous. But if solid and liquid substances can have a color, which is the main sign for the visual determination of chemical compounds, then gases in most cases do not have a color. Then the question arises, how to recognize gases? It turns out that not everything is so complicated and with the help of simple techniques, as well as by some properties, it is possible to completely determine gaseous substances.
It is necessary
Glass for collecting gas, matches, torch
Oxygen. Collect it by displacing air or water. Since it is heavier than air, the container does not need to be turned over, but simply to collect gas in it. To determine that this particular gaseous substance has been obtained, it is necessary to introduce a smoldering splinter into the vessel with oxygen, which will flare up with a bright flame. Since the gas supports combustion, therefore, it is oxygen that is in this container.
Hydrogen. It is a colorless and odorless gas, lighter than air. Therefore, it is collected by displacing water or air, but the container is kept upside down. After collecting, the vessel is immediately closed. In order to recognize a substance, a container with hydrogen is opened and a lighted match is immediately brought to the hole. A groin cotton is heard. It is this cotton that indicates the presence of hydrogen in the vessel.
Carbon dioxide. This substance is heavier than air, and therefore can be collected directly into a glass by air displacement. In order to determine that carbon dioxide has been collected, you need to add a smoldering torch into the container with it. The fact that the fire will go out immediately is a sign of the presence of carbon dioxide, as it does not support the combustion process.
Ammonia. It is a gaseous substance and can be immediately identified by its pungent, suffocating odor. The same "aroma" has ammonia, which is used in case of loss of consciousness.
Nitric oxide (IV). It is a gas, even visually detectable, since its other name is "fox tail", which appeared due to its brown color. Brown gas is very poisonous and categorically contraindicated in an unprotected situation (only under traction).
Methane. By itself, it is a colorless and odorless gas, however, for safety reasons, special "odorous" substances are added to it, which help to recognize methane and prevent emergencies.
Ozone. It is a gaseous substance that everyone feels after lightning discharges. It is ozone that gives the feeling of freshness after a rain with a thunderstorm. Thus, there is one answer to the question: "How to recognize gases" - to use the simplest skills and techniques learned in chemistry lessons.