When carrying out some experiments it is necessary to remember that it is possible to increase the speed of chemical reactions. For this purpose there are certain conditions, for example, to increase temperature enough, to crush substances, to pick up catalysts or to use more concentrated reagents. What can reaction speed depend on?
It is required to you
- - heating device;
- - reactants;
- - laboratory glassware.
Instruction
1. The nature reacting veshchestvv dependences on it with some connections reaction passes instantly, and with others slowly (or does not go at all). For example, lower a sodium piece in water then you will observe impassioned chemical reaction which proceeds with allocation of heat and light (sparks appear). Now take other, less active metal, let us assume, iron, and also lower it in water. Visual changes will not be owing to insufficient activity of this substance. However several days of change later nevertheless will occur as iron will begin to corrode.
2. TemperaturaSushchestvuet the rule according to which, at temperature increase on 10 ° the speed of reaction increases by 2-4 times. For example, take black powder of oxide of copper, place it in a test tube and flow to it a little solution of sulfuric acid. At the room temperature the change of coloring will be shown not at once, however it is worth heating the capacity as solution at once will get characteristic coloring of dark blue-light blue color as copper sulfate was formed.
3. KontsentratsiyaPri increase in concentration of the reacting substances speed also increases. For example, take a wooden splinter, set fire to it and shake a flame. On air in which oxygen only of 21%, you will observe decay. Now bring it in pure oxygen then the flame will brightly flash as there oxygen concentration in 5 times more.
4. Surface area reacting a reaction veshchestvskorost directly depends on this factor by the principle - the more the total surface of reagents, the reaction speed is higher. In other words, the substances more small reacting, the are higher the speed of their interaction. Therefore chemical process between the connections which are in the dissolved look proceeds instantly. For example, mix powder of chloride of ammonium and hydroxide of calcium and crush them in a mortar. In a few minutes feel an unpleasant smell of ammonia. Conduct the same experiment, only using substances in the form of solutions. At once determine by the speed of emergence of a smell that reaction goes much quicker.
5. DavlenieChtoba to increase reaction speed, it is necessary to increase pressure. In this case the distance between the reacting particles becomes minimum that provides their interaction. However special conditions are for this purpose necessary.
6. KatalizatorVeshchestvo, sharply increasing reaction speed, is called the catalyst as which even water can act. For example, take the aluminum crushed in powder and small kristallik of iodine, mix them among themselves – visual changes will not be. By means of the pipette add a water droplet – very impassioned reaction will go, that is water acts as the catalyst, accelerating process, but itself does not participate in it.