No.
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Name, Estimat-ed Time
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Objective
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Safety precautions
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Procedure (Include Q about the procedure and their A)
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Prediction
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Observation, explain, equation
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1.
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Preparation of nitrogen
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Help students konw
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The air duct must be stored before storing the alcohol lamp to avoid causing an explosion
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Take 3ml of saturated NH4Cl solution in a test tube. Close the stopper with the gas tube, install the test tube. Lightly heat. Capture nitrogen gas by pushing water
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The mixture boils, there are air bubbles coming out and pushing the water out of the flask
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Observation: The same as prediction
Explain:
NaNO2 + NH4Cl -> NH4NO3 + NaCl
Because the NH4NO3 producted is unstable, it immediaely decomposes
NH4NO3 -> N2 + 2H2O
Because N2 is sparingly soluble in water, we collect gas by repelling water
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2
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Nitrogen’s inability to sustain
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Help students know the non-combustible and life
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a) Non-life-sustaining
Put a grasshoper in the N2 gas tank. Stopper the bottle (do not shake)
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After a short time the grasshopper moving and died
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Observation: The same as prediction
Nitrogen gas does not sustain life
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3.
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Preparation of Ammonia
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Help students know how to prepare ammonia gas
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Be careful with heat
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From ammonium salt and alkaline
Take about 2 grams of NH4Cl and 1 gram of powdered lime into a porcelain mortar, mix well, and then pour the resulting mixture into a dry heat-resistant test tube. Close the test tube with the stopper with the air tube through.
Place the test tube in the rack horizontally, the mouth slightly lower than the bottom.
Collect air directly into an inverted and dry conical flask. At the mouth of the receiver, press the outside of the moist red litmus paper. When the litmus turns green, stop cooking. Close the receiver tightly and then return it.
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When heating the mixed mixture, we see that the gas escapes to the collector. Moist purple litmus gradually turns blue
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Same as predicted.
Explain: Because when ammonium chloride (NH4Cl) and lime powder are heated, ammonia (NH3) is obtained
NH4Cl → NH3 + HCl
and ammonia, when dissolved in water, will produce basic hydroxide, so blue litmus will turn blue.
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4.
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Solubility of ammonia
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Help students understand the solubility of ammonia
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U se the ammonia gas (NH3) cylinder just obtained in the 3rd experiment. Cover the flask with a rubber stopper fitted with a pointed air duct, the pointed end of the tube is inserted into the inside of the flask. Cover the end of the air duct with your finger and turn the container filled with ammonia (NH3) upside down into a glass basin filled with water with a few drops of phenolphthalein added. Open your finger. Observe what happens and write equations for the reactions.
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Water sprayed in a pink jet into the ammonia gas (NH3) tank.
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Observation: Same as predicted.
Explain: Ammonia gas sprayed into the bottle into pink rays due to its solubility in water, the pressure of the ammonia gas in the tank suddenly decreased, the water in the cup was sucked into the bottle through the glass tube and then sprayed into jets.
Adding basic ammonia causes phenolphthalein to turn pink
⇒ the jets of water that spew out are pink.
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7.
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Pyrolysis of ammonium salts
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Help students know how and understand the process of pyrolysis of ammonium salts
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Be careful when using heat
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Put a few crystals of ammonium chloride in the first test tube. Put a few crystals of ammonium nitrate in the second test tube
Pair of test tubes on rack. Heat the bottom of the test tube. Place the glass plate over the mouth of the first test tube, and place moist blue litmus paper over the mouth of the second test tube.
Observe the phenomenon and explain.
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- The first test tube with glass has some crystals deposited on the glass
- The second test tube litmus paper gradually turned blue
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Same as predicted.
Explain: The first test tube, when heating ammonium chloride, decomposes to form ammonium and hydrochloric acid, but this is a two-way reaction, so catching the glass plate in the acid and ammonia vapors together will create some ammonium chloride crystals.
- In the second test tube, pyrolysis of ammonium nitrate at 210oC will have: 7NH4NO3 → 6NH3 + 8NO2 + 5H2O
When ammonia meets moist purple litmus, it produces hydroxide ions that turn litmus blue
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8.
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Preparation of nitric acid from nitrate salts
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Help students know how and understand the process of pyrolysis of ammonium salts
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Be careful when using acids and heat
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Put in a test tube 1 gram of potassium nitrate, then add about 2ml of concentrated sulfuric acid (can use ammonium nitrate instead of potassium nitrate).
Install the tool as shown in Figure 5.12. Use an alcohol lamp to heat the test tube so that the formed nitric acid flows drop by drop into the conical flask.
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The mixture reacts and produces nitric acid gas in the collector when it is cold, the gas will condense to form nitric acid drop by drop.
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Same as predicted.
Explain:
Sulfuric acid reacts with potassium nitrate with the react:
KNO3 + H2SO4 → HNO3+ KHSO4
and nitric acid produced in the form of vapor, when cold, it will condense into drops
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11.
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Soluble adsorption of wood charcoal
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Help students know the adsorption of solutes of wood charcoal
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Take a large glass tube, one end with a stopper with a conduit. Place a layer of cotton over the button. Pour a layer of wood charcoal on top about 1cm thick. On the coal lined another layer of cotton. Pour the dilute ink solution into the glass tube.
Use the drip cup at the bottom as shown. Comment on the water obtained in the beaker compared to the solution in the glass tube above.
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The dilute ink water slowly penetrates through the wood charcoal layer and the cotton layer and obtains an aqueous solution in a transparent cup.
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Observation: Same as predicted.
Explain: The large internal surface area of carbon creates an attractive force to attract other molecules. These attractive forces will cause dirt to be adsorbed (or adhered) to the carbon surface.
The adsorbed solutes will move from the area of light pore to those with the strongest gravitational force. Pollutants are adsorbed because the attraction of the carbon surface is much greater than their attraction in the water.
Contaminants that are organic will be high molecular weight, neutral or nonpolar, chemically they are easily adsorbed by activated carbon. In order for organic pollutants to be adsorbed by carbon, they must be dissolved in water so that the size is smaller than the pore size of the carbon. So the water after passing through the coal layer will be transparent.
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