The monthly test is coming soon. Teacher Ruidete will tell the students about the common gas. Everyone can write it down and hope to relieve the students a little pressure!
(1) Physical properties
1, after the pressure is lowered, the oxygen will turn into a light blue liquid; continue to pressurize and cool down, it will turn into a light blue snowflake Solid.
2, solid CO2 is called dry ice, easy to sublimate.
(4) generating device
——Selection basis—reactant state (solid or solid-liquid mixing); reaction conditions (whether heating is required)
solid heating type
solid liquid Normal temperature type
(5) Collecting device
——According to gas density and solubility in water
Down air method
Up Exhaust air method
Drainage gas collection method
(6) Operation steps and precautions
Operation procedure for heating KMnO4 or a mixture of KClO3 and MnO2 to produce oxygen
( 1) Check (harmonic-tea): check the airtightness of the device;
(2) Install (harmonic-zhuang): load the medicine (if it is made of potassium permanganate, plug in the test tube Cotton, preventing potassium permanganate particles from entering the conduit to block the conduit).
(3) Fixed: Fixing device (the iron clip is clamped about 1/3 from the tube mouth; the tube mouth is slightly inclined downward to prevent the condensed water from flowing back and causing the tube to burst).
(4): Start the heating with the alcohol lamp (must preheat it first, then use the alcohol lamp to heat the drug part).
(5) Receiving: Collecting gas (can only be collected when bubbles are continuously and evenly emerged, and the gas that was previously discharged is the air in the test tube).
(6) away (harmonic-profit): The catheter is evacuated from the sink.
(7) Extinguished (harmonic-interest): Extinguish the alcohol lamp. The last two steps cannot be reversed, otherwise the water in the sink will flow back into the test tube, causing the test tube to burst.