High School Chemical Separation, Purification and Calculation Topics with Process

1.First, an excess of BACL2 was added to remove the sulfate ions in K2SO4, then an excess of potassium carbonate was added to remove the excess barium chloride and calcium chloride, then an excess of potassium hydroxide was added to remove the magnesium chloride, and finally dilute hydrochloric acid was added to remove the excess potassium carbonate and potassium hydroxide.

m=n*m=quality) is more difficult than it. Volume ratio = ratio of material quantity Use n = m m m to find the n ratio of o2.

Ratio of the number of molecules = ratio of the amount of matter.

Atomic number ratio = NO2*2 NCO2*3

Note that the premise is under standard conditions.

3(1)n=m/m=

Number of oxygen atoms = 2) n = v vm =

Number of hydrogen atoms = 3) n = m m = 8g 80 =

Number of atoms =

1。(1) Prepare the solution (2) first add a sufficient amount of BACL2, filter, remove sulfate, (3) then add a sufficient amount of K2CO3, filter, remove Ca2+, and the remaining Ba2+ in the previous step, (4) finally add KOH, filter, remove Mg2+, (4) add a sufficient amount of HCl, remove the remaining carbonate and hydroxide, (5) evaporation crystallization. Note:

It is necessary to remove the sulfate first and then Ca2+, otherwise Ba2+ will be introduced. Filtering can be filtered together at the end, but the effect is not as good as filtering separately.

For, for, mass ratio: 11. At the same temperature and pressure, the volume ratio is equal to the ratio of the amount of matter, so it is 1:

2。The ratio of the number of molecules is equal to the ratio of the amount of matter, which contains 2* oxygen atoms, carbon atoms and oxygen atoms, and co-atoms, so the ratio of atoms to numbers is 1:3.

3。(1) The relative molecular mass (or molar mass) of nitric acid is 63, and the oxygen atom contained in it is Avogadro's constant).

2) Under the standard condition, hydrogen containing atoms, pcs.

3) The relative molecular mass (or molar mass) of SO3 is 80, and 8GSO3 is containing sulfur atoms, oxygen atoms, and common atoms.

You should have just entered high school, and you can't understand the concepts of quantity of matter and molar mass.

Detached instances:

For example, when rice is processed into rice in rural areas, sieves are often used to separate rice from bran. Gauze bags are commonly used to separate tofu residue from soybean milk in rural areas; When washing rice, the pouring method is often used to separate the washing water from the rice; When there is more oil mixed in the water and stratified, the upper layer of oil can be gradually sucked out with a straw; When iron filings and copper filings are mixed together, they can be separated by magnets, etc.

Examples of purification:

Extraction of iodine from kelp, extraction of table salt from seawater, extraction of bromine from seawater, desalination of seawater, and refining of various chemicals: coarse salt to refined salt, production of anhydrous alcohol, etc.

Is gutter oil an example of purification? Hehe, I think I can have a chat with the teacher.

The main separation and purification methods in high school are as follows:

Crystallization and recrystallization.

nacl(kno3)

Impurities are in parentheses, the same below.

Distilled ethanol (water): Add enough fresh CAO and then distill filter NaCl solution (CaCO3).

Sublimation of NACL

i2) Iodine is removed by heating.

kno3（nh4cl）

Extraction method: The bromine element in bromine water is extracted with benzene ccl4.

Dissolved iron (Al).

Add sodium hydroxide solution to dissolve aluminum.

Saturated sodium bicarbonate solution for increasing CO2 (SO2);

Co (CO2) with scorching C

For example, in the conversion method, Fe(OH)3 is separated, and a sufficient amount of sodium hydroxide solution is added to remove Al(OH)3 and Fe(OH)3 is separated

Excess CO2 was then introduced into the sodium tetrahydroxyaluminate solution to convert it to Al(OH)3FeCl2 (FeCl3).

Add iron powder; FeCl3 (FeCl2) is introduced into the solution

1.The main glass instruments for removing silver chloride (filtration) from salt water are beakers, glass rods, and funnels.

2.The principle of separating Kno3 and NaCl powder (crystallization) is that the solubility of Kno3 varies greatly with temperature, and the solubility of NaCl varies little with temperature.

3.The principle of separating water and alcohol (distillation) is that water first reacts with CaO to form Ca(OH)2, and the boiling point of Ca(OH)2 is much greater than that of alcohol, so it can be distilled.

4.The principle of obtaining iodine from iodine water (extraction) is that the solubility of iodine in CCL4 is much greater than that in water.

5.The principle of separating CCL4 and water (separating) is that Ccl4 and water are not miscible with each other, and the instrument is a separating funnel and beaker.

Strain glass rods, beakers.

Recrystallization The solubility of sodium chloride does not change much with temperature.

Distillation Alcohol volatile Alcohol lamps, flasks, glass rods, beakers, extractions Similar to each other.

Dispensing different densities of separating funnels, beakers, glass rods.

1 funnel. Glass rods. Beaker.

2. The principle is: although the speed of the change of temperature of the two substances is large.

3 fractionation, the boiling point of the two is different, distillation flask, thermometer, condenser tube, horn tube, Erlenmeyer flask, 4 quenching. The degree of resolution of iodine elemental in water varies greatly from that in quenching agents. 5

1. Beaker, glass rod, long-neck funnel.

2. The solubility of NaCl and Kno3 varies with temperature, the solubility of NaCl does not change much with temperature, and the solubility of Kno3 changes greatly with temperature.

3. The boiling point of alcohol and water is different from that of alcohol lamp, distillation flask (long-necked or short-necked round-bottom flask), distillation head, thermometer, condenser tube and horn tube, beaker.

4. The solubility of iodine in carbon tetrachloride is much greater than that in water, and distillation after extraction 5. Ccl4 is incompatible with water Ccl4 is a non-polar molecule, water is a polar molecule, and the two are incompatible.

I'm glad to answer your chemistry questions.

There are two methods for the separation and purification of mixtures: physical and chemical.

First of all, physical methods: the use of different properties of substances (such as: melting and boiling point, freezing point, solubility, color, odor, density) to judge the common elimination number methods are:

Distillation (purification of substances according to different boiling points), filtration (separation of solid and liquid mixtures), extraction, decanting, dissolution, crystallization, fractionation, adsorption, sublimation.

The important thing is the chemical method, first of all, the principle (do not introduce new impurities, do not consume the amount of the purified substance, and the experiment should be simple and easy).

Chemical Methods:1Generative precipitation method (example: crude salt purification in textbooks) 2Gas generation method.

3.Redox method.

4.Positive salt and acid salt conversion methods.

5.Ion bridge exchange method.

If you have any questions, please ask them in a timely manner.

Salting out is not familiar, but recrystallization refers to repeated crystallization, which is a rope placed on a flask, and this small solid particle is hung on the rope, and after a long time, the particle becomes larger, becomes a crystal, and then the crystal is broken, and a small piece is taken and crystallized again, I don't know if you know the semi-permeable membrane.

Dialysis is a process that uses small molecules and small ions that can penetrate a semi-permeable membrane, but colloidal particles cannot permeate the semi-permeable membrane, and remove small molecules or ions as impurities from the sol. During dialysis, the colloidal solution is placed in a dialyzer composed of a semi-permeable membrane, and the dispersion medium (usually water) of the colloidal solution is changed regularly outside the dialyzer to achieve the purpose of purifying colloids. During dialysis, the applied direct current electric field can often accelerate the diffusion of small ions from the inside of the membrane to the outside of the membrane, which is called electrodialysis.

A selective permeability method for separating particles of different solutes using semipermeable membranes. Dialysis of charged solute particles (such as ions, colloidal particles, etc.) in solution under the action of an electric field is called electrodialysis.