So: alcohol lamp.
(2) Using potassium permanganate to make oxygen needs heating, and the device to be selected is device A. The method to test the airtightness of this device is: after connecting the device, first put the catheter into the water tank, hold the test tube in your hand, and observe whether there are bubbles in the catheter, which can prove that the device is airtight;
The function of putting a ball of cotton at the mouth of the test tube is to prevent potassium permanganate from entering the catheter.
Therefore, fill in: a; After connecting the device, first put the catheter mouth into the water tank, hold the test tube in hand, and observe whether there are bubbles coming out of the catheter mouth, which can prove that the device is watertight; Prevent potassium permanganate from entering the catheter.
(3) If the oxygen is collected by upward exhaust, the way to check that the oxygen has been collected completely is to put the wooden strip with Mars on the bottle mouth. If the wooden strip with mars is rekindled, it means that the collection has been completed.
So fill in: put the wooden strip with mars on the bottle mouth. If the wooden strips with Mars are rekindled, the collection is full.
(4) If oxygen is prepared by device B, it should be prepared by hydrogen peroxide, and the chemical equation of hydrogen peroxide decomposing into water and oxygen under the catalysis of manganese dioxide is: 2H2O2? MnO2？ . ? 2H2O+O2↑。
Therefore, fill in: 2H2O2? MnO2？ . ? 2H2O+O2↑。