Lesson 2
The experimental part.
This experiment should be carried out exclusively in the presence of a teacher and in the chemistry room (laboratory).
Carefully study the safety rules for working with chemical utensils and reagents!
Do not try to repeat the experience at home!!!
HYDROGEN IS AN EXPLOSIVE GAS!
Before starting the experience, read the step-by-step instructions in advance!
Experiment No. 1. Synthesis of hydrogen from aluminum
Required materials:
– needle from a syringe
– 3 capacities
– aluminum foil
– caustic soda (sodium hydroxide NaOH) or baking soda (sodium bicarbonate NaHCO3)
– water
Step 1. Put on gloves and goggles for safety!!!
Pour 150 ml of water into a container with one outlet on the lid, add about 1 tablespoon of alkali. Move it.
Step 2.
Then pour the dist of water into the second container with two outlets (1 hose -shorter does not touch the water, 2 hose-longer and immersed in water). Close the lid tightly.
Step 3. Place the second hose connected to the needle from the syringe horizontally.
Pour 150 ml of water into a container with one outlet on the lid, add about 1 tablespoon of alkali. Move it.
Step 6. Immediately complete the process in stages:
1. Extinguish the flame by immersing the syringe in clean water
2. Carefully open the first container where the chemical reaction takes place. Then carefully remove the pieces of foil from the solution. Neutralize the foil by pouring clean water. Throw it in the trash.
3. And neutralize the remaining solution with running water under the sink.
4. Treat the work surface with wet wipes.
5. Throw the gloves in the trash and wash your hands.
DO NOT REPEAT THIS PROCESS OUTSIDE OF THE CLASSROOM!!!
Step 7. Answer the questions:
1. Complete the reaction:
Al + H2O + NaOH = _________________________________________
Is it an oxidation or reduction reaction?
2. Describe the whole process. What characteristic signs have you observed?
3. What type does this chemical reaction belong to? (there are 4 types: addition, decomposition, substitution, exchange)
4. According to the thermal effect, what type does this chemical reaction belong to? (exothermic reaction/endothermic reaction)
4. How many degrees do you think there were in the first container?