Urgent! Ten questions about oxygen production in laboratory

1, to prevent water vapor condensation from heating the bottom of the test tube and causing the test tube to burst.

2. If the air tightness of the device is not good, there will be air leakage during the experiment, which will lead to impure oxygen collected or difficult oxygen collection.

3. Place the catheter below the liquid level in the sink, and then cover the test tube with your hands. If there are bubbles coming out of the catheter, a water column will be formed in the catheter after releasing the hand, so the air tightness is good.

4, to prevent potassium permanganate powder from entering the catheter and blocking the catheter.

5. Because oxygen is not easily soluble in water, drainage method can be used to collect oxygen, and at this time, the catheter port can be placed at the gas container port.

6, because the density of oxygen is slightly greater than the density of air, so the bottle mouth should be upward, at this time, the catheter should be set at the bottom of the cylinder.

7. Because the air in the test tube is decomposed by heat at the beginning, if it is collected immediately, the collected oxygen will be impure.

8. Prevent the water in the sink from flowing back to the bottom of the heated test tube and causing the test tube to burst.

9. When collecting by drainage method: when bubbles emerge from the gas container, they will be full; When collecting by upward exhaust method: put the wooden strip with sparks on the bottle mouth, and the wooden strip will be full when it is rekindled.

10, stick a stick with Mars into the gas container. When the stick is rekindled, the colorless gas in the bottle is oxygen.