There are 3 methods for the preparation of solutions of the given concentrations: 1. The sampling of the solid substance 2. Devilization of a more concentrated solution. 3. Fixanal.

Preparation of a solution from a tv hanging. Substances.1.Read a mass of substance. 2. Calculate the calculation. 3. Listened on analytical scales (for the preparation of primary standard solution) or on the technical (for the preparation of the secondary). 4. Perform a hitch to the measuring flask of the desired volume. 5. Add water to the flask to the label and mix. 6. Standing the secondary standard solution.

Preparation of a solution from fixanal.1. Emit a measuring flask in accordance with the desired volume of the prepared solution. 2. Amend the ampoule of Fixanal and smash the thieves over the funnel in the flask. 3. Perform the contents of the ampoule through the funnel into the selected measuring flask. 4. To the ampoule through the funnel in the flask. 5. Add water to the flask to the label and mix.

Preparation of a solution with diluting conc. Solid.1. Conduct the density of the original concentrated solution using the hydrometer. 2. Calculate the calculation of the volume of the concentrated solution. 3. Treatment of the required volume of concentrated cylinder solution. 4. Perform a concentrated solution: a) to the dimensional flask of the desired volume, b) to the non-meter chemical dishes for the preparation of the solution with the mass fraction of the substance in the solution. 5. Add: a) water to the measuring flask to the label, b) the calculated volume of water into the appropriate chemical dishes. 6.Recery mix.

6. What is the titrimetric analysis? What rule is based on this method. Specify its mathematical expression. What requirements are imposed on the reactions underlying the titrimetric analysis.

Tutrimetric analysis - The method of quantitative analysis based on the accurate measurement of the volume of the reagent solution consumed to the equivalent interaction with the determined substance.

Requirements: 1. The substances that react must respond into strictly defined quantitative relations. 2. Reaction must leak quickly and quantitatively, that is, be practically irreversible. The equilibrium constant should be large. 3. Reaction should, if possible, flow at room temperature. 4. The equivalence must be recorded sharply and accurately. 5. Titration should not be accompanied by side reactions.

The law of equivalents: In chemical reactions, the number of equivalents of all substances that have entered the reaction and formed in it are always equal to each other.

Mathematical expression: C (F eq a) * V (a) \u003d C (F eq b) * V (b)

7. What is called the titrant (standard solution). Specify the basic ways to prepare the titrant.

Tartran (Standard solution) - a solution of an analytic reagent with a precisely known concentration used to find the quantitative content of the determined substance in solution.

Methods of cooking:

a) The primary standard solution (source) is a solution prepared from a standard (installation) substance, the concentration of which known by weight of this substance in a certain amount of solution. Using these solutions, the concentration of working solutions is established.

b) Working solution (secondary standard solution) is a solution, the concentration of which is established by standardization. With the help of working solutions, tutrimetric definitions are carried out.

8. Is it possible to prepare a standard solution Naoh. on exact hide? If so, how? If not, why? Reply explain the answer. By accurate hide, you can prepare only solutions of such substances that satisfy the requirements for installation substances. Installation substances are stable, chemically pure compounds of precisely known composition, substances that are stored during storage and in solid form, and in solution.

NaOH and KOH - caustic alkalis, which are absorbed from the air moisture and carbon dioxide and change their composition even in the process of weighing, that is, they do not meet the requirements for installation substances and to prepare their standard solution will not be possible.

The titrant of these solutions prepare an approximate concentration, diluting with water 50% solution (sodium carbonate solubility in a concentrated solution of NaOH small), and then standardize it according to the dihydrate of oxalic acid.

9. Apply how the working HCl solution is prepared. What installation substances are used to standardize the solution and why? Write the equations of the corresponding reactions. 1) Measure the density of the original (concentrated) solution of HCl using the areaometer and on the reference table to find a mass fraction of acid in solution. 2) Calculate the molar concentration of the acid in the initial (concentrated) solution by the formula: C conc (HCl) \u003d W (HCl) * P (HCl) * 10 / m (HCl). 3) Calculate the scope of the original (concentrated) solution of HCl, which is necessary for the preparation of the P ray of a given concentration: VKONC \u003d VKUB * C (HCl) / SCONC (HCl)

4) pour distilled water to the measuring flask for 250 ml, measure the calculated volume of the concentrated solution using the measuring cylinder and carefully pour it into a measuring flask, rinse the measuring cylinder 2-3 times with distilled water, merging the flushing fluid into the same flask, then bring the volume Solution up to 250 ml by distilled water. The resulting solution thoroughly mix and determine the exact concentration of HCl in the resulting solution. Setting the concentration of hydrochloric acid over sodium tetraborate formed by a strong base and weak acid:

The basis of the standardization method of the HCl working solution is the following reactions:

a) sodium tetrastruct hydrolysis: Na2B4O7 + 7H2O \u003d 2NAOH + 4H3BO3 with the formation of an equivalent amount of alkali, which is removed by a HCl solution in the presence of a methyl approach;

b) The interaction of the formed alkali with chloride acid: HCl + NaOH \u003d NaCl + H2O. The total reaction equation is: Na2B4O7 + 2HCl + 5H2O \u003d 2NACL + 4H3BO3.

Depending on the material of the plastered surface apply various solutions. Solutions consist of binding, aggregate and water, in addition to simple solutions consisting of one binder and aggregate, there are also mixed or complex solutions consisting of two binders and aggregates. Solutions for conventional plasters are clay, lime, lime-gypsum, cement and cement-limestone (mixed). It is necessary that the plastering solution sticks well to the surface and easily spilled with thin layers without breaking. All prepared solution should be the same composition. This makes it possible to get a plaster crust of the same porosity and strength.

Hydish, solutions should have the same shrinkage and should not give cracks.

§ 1. Plaster solutions

Mortar Apply to plastering internal and external surfaces on brick, concrete and wood. On wooden surfaces, it requires a long time to set. Lime solutions are plastic, wellclosed with all types of surfaces and are very durable in dry, not subject to damp, places.

The prepared solution must have normal luggage and fat.

The easiest way to determine the fatty solution is that the solution is lowered in the solution, and then removed and look at how much the solution was poured on the paddle. If the solution does not stick to the weft, then it is skinny, and if the solution sticks a lot, the solution is greasy. With a normal solution, it only slightly covers the paddle. Sands are added to fatty solutions, and in skinny - binders.

Lime solutions with slow lifetimes can be used in case during the week. The disadvantages of the lime solution should include its particularly slow grasp when applied to wooden surfaces.

To accelerate the setting of the lime solution, plaster adds to it, obtaining a lime-gypsum solution. This solution is used mainly to plastering internal wooden surfaces and sometimes outdoor, not exposed to moisture.

Lime-based gypsum solution is prepared by the following way. Water poured into the box, then gradually fall into it plaster, then everything is quick and thoroughly mixed until then. Until the liquid gypsum dough without lumps. This dough add a lime solution and stirred vigorously until a homogeneous mass is obtained. The portion of the solution is quickly stirred and are used in 5-7 minutes (if the solution is to breed at the same time, it can grasp).

The portion of the lime-gypsum solution is called a factory. Usually, three parts of the lime solution are taken to prepare the factory for one piece of gypsum. The factory is stirred by a stirrer.

The cement mortar is plastered by the systematic exposure to water surfaces in bathrooms, baths, pools, laundry, dreeshes, and restrooms.

Cement mortar For plastering works are prepared from the cement mixture of 1: 1, 1: 2, 1: 3, 1: 4. On one part of the cement take from one to four parts of the sand. For the preparation of the cement mixture, the required quantities of cement and sand are measured in the desired proportion and pour them with layers: layer of sand, cement layer, etc., so that the mixture is mixed faster - moved. The bulky materials are thoroughly mixed with plaster blades. To obtain a more uniform mixture, it is desirable to sift through frequent sieve. Dry mixes in large quantities need to be mixed in concrete mixers. It is much faster and more productive.

Cement solutions of compositions up to 1: 3 plastic. With an increase in the amount of sand, they become tougher and worse to work with them. Preparing a dry mixture, it is inducing to water, receiving a cement solution, which should be used in case no later than 60 minutes after cooking.

More plastic are cement-lime solutions, so-called mixed. Mixed solutions are used to shock the exterior and inner parts of the building. For their preparation, the dry cement mixture is imposed not with water, but by lime milk. Mixed solutions for plaster works are prepared as follows: 1: 1: 6; 1: 1: 8; 1: 2: 8 and 1: 3: 12 (cement, limestone dough, aggregate).

Solutions on the oversized hammer of the lime of Ing. I. V. Smirnov proposed to apply a ground-haired lime-boiler instead of a limestone test. Therefore, if digging of creative holes are required to prepare usual lime, the lime quenching, time to maintain it in the worklines and the cost of working force on the recess from the pit, then the commercially lime together with all the incomplete and the ignition is grinding in the ball mills to the subtlety of the cement.

For the inner plaster performed in the summer, it is recommended to prepare solutions on the ground-boiling harness of the 1st grade of the following volume by volume: 1 part of the thinness of the lime of the boiler; 1 part of clay; 6-7 pieces of sand; 1 part of the hammer of the lime-boiler; 0.5 parts of clay; 3.5-4 pieces of sand; 1 part of the hammer of the lime-boiler; 0.3 pieces of gypsum; 4-5 pieces of sand; 0,5 pieces of the hammer of loving boiler; 0.5 parts of clay; 0.3 pieces of gypsum, 4-5 pieces of sand, 1 part of the hammer of loving boiler; 4-5 pieces of slag sand; 1 part of the hammer of the lime-boiler; 0.5 parts of cement; 3.5-4 pieces of sand.

Solutions on the oversized hammer of wing boil should be previously tested on separate samples. If the samples are unsatisfactory, will be default, crack and so on, the solution must be made secondary.

These solutions followed after their preparation to withstand 30-40 minutes and only after that apply to the surface. This is necessary so that the solution does not breathe too quickly on the surfaces, in hot weather, the plaster should be sprayed with water one time per day in a continuation of 5-7 days.

With a manual method, preparation of such solutions first prepare a dry mixture of ringing ground, sand and cement and then all shut down with water. If clay is included in the solutions, then it is added as a clay milk on which the mixture is shown. If the gypsum is added to the solution, then the dry mixture should be prepared at first, dilute the liquid gypsum solution and create a mixture on it.

Preparation of plaster solutions on the hammer of negascinated lime requires caution, as the resulting lime dust adversely affects the lungs.

Little solutions.From excess water, liquid solutions that give loose plaster are obtained; With a lack of water, thick, difficult to surface. The more water in solution, the slower the solution is seized, the lower strength has plaster. For work, we need solutions of different density, which is determined by the cone construction.

The thick solution, the less the cone is immersed in it and vice versa. To perform various plaster layers, a solution of different density is used, characterized by the depth of the cone immersion.

For spraying with a mechanized applying solution, the depth of immersion of the cone must be 9 cm.

The same, when manually applying a solution ..... 12 cm

For soil, regardless of the method of applying a solution ..... 7-8 cm

For crossbar solutions containing plaster ..... 9-12 cm

For the crossbar with solutions without plaster ..... 7- 8 cm

Waterproofing solutions. To give walls, floors or other designs full waterproof, cement solutions Prepared with the additives of ceresite or soluble liquid glass. For the preparation of such solutions, a dry cement mixture of composition from 1: 1 to 1: 3 is prepared, it is thoroughly stirred, after which the cerestic emulsion is prepared.

For this, it takes 1 volume of the cerezite, pour it into 8-10 volume parts of water and everything is thoroughly stirred until a homogeneous emulsion is obtained, on which the cement mixture is mixed. The resulting solution must be used in the case no later than an hour.

Plaster layers should be applied with a thickness of each no more than 10 mm, Otherwise, the layers of the solution will fill and fall off.

Such solutions can be applied to raw surfaces.

Solutions prepared on soluble glass are collected very quickly (after 2-5 minutes), on the basis of this, they should be prepared by small portions (1-2 l) And immediately use a thing. The cement mixture is mixed not on water, but on a solution of liquid glass, for the preparation of which 1 part of the liquid glass is mixed with 5 or 10 parts of water until a homogeneous emulsion is obtained. The less water takes on 1 part of the soluble glass, the faster the solution is seized and vice versa. The prepared solution is used for temporary insulation of the surface from the effects of groundwater. Then cement mortar is applied on such a layer.

§ 2. Methods of preparation of solutions

Getting started to prepare a solution, it is necessary to sift all materials.

Sand for the preparation of spray and soil sieved through a sieve with cell sizes from 5 x 5 to 10 x 10 mm. Sand for the preparation of the crossbar, as well as cement and gypsum sift through a sieve with the size of 2x2 cells mm.

Sand sifting is made manually and with the help of machines manual sieve should be used only for sieving small portions of sand. Manual sieves are in the form of a sieve or in the form of a frame with two handles.

The fastest sifting of sand is carried out on the mechanical sieves, which are often called peckasels. Pesketkeepers are of a wide variety of designs. The sand supply to the sandbreaker is performed manually. Sita is given in Action by the electric motor.

The solutions are prepared by mechanically and manually.

Preparation of solutions in solids

For the preparation of solutions, solidization is used in various designs and performance, periodic and continuous action. Solution C-50 brand has a beam 80 capacity l Productivity 9.0-10.0 m 2. Solution in shift. This solution is convenient to operate, its weight is small, about 470 kg. Solution C-104 brand with drum capacitance 150 l. Manufacture 24-29. l 3. Solution in shift. Its weight is about 1150 kg.

In addition to these solution, there are a number of others, with a tank of a drum from 325 to 750 l. (Fig. 8).

Fig. 8 Solution C-219

Loading materials, for example, in a mixing drum of the C-104 solution, produced in a dry form using a loading bucket moving along the inclined guide. In the mixing drum, the materials are mixed with blades, fortified on the rotating shaft. Water is measured and poured into a mixing drum from a water tank located above the mixing drum. At the end of the mixing, the solution by tipping the drum is unloaded into the box, from which it enters the bunker of the mortar pump or bottled into the car. After emptying the drum is placed in place and a new portion of materials is loaded into it.

Preparation of solutions manually

Preparation of a solution manually in plasterboxes is made at a small volume of plastering and repair work.

For the preparation of a lime mortar, a limestone dough is placed and stirred well. For the speed of the stirring, first pour into the lime some of the sand, then gradually add all the sand and mix well with the dough. In solution there should be no limestone lumps and clusters of unsolved sand. If there are limestones in the limestone dough, the dough is passed through a sieve with holes from 5 x 5 to 10 x 10 mm.

Depending on the fat content of lime, lime plaster solutions are the following compositions: 1: 1; 1: 1.5; 1: 2; 1: 2.5; 1: 3 and 1: 4 (first digit - limestone dough, second - aggregate).

Construction solid called artificial stone material obtained by hardening a properly selected mixture consisting of a binding, small foggy-body, water and additives. Before the start of solidification it is called ras-creative mixture.

Building solutions are classified in density, type of binder, composition and intended purpose.

Middle density distinguish solutions heavy densitymore than 1500 kg / m and lungsdensity less than 1500 kg / m.

By type of astringent solutions are lime, hypots, cement and based on mixed binders. Depending on the properties of the binder solutions divided into airair-dry conditions (for example, lime, gypsum), and hydraulic, beginning to harden on the road and continue to fit in water or in wet conditions.

According to the degree of readiness solutions are divided into: dry mixesand mixed mixtures,ready to use.

According to the compositionsolutions are divided into simple and complex (mixed). Solutions cooked on one binder fill-le and water called simple.The compositions of simple solutions are denoted by two numbers. For example, a lime solution of SO-Stava 1: 4 means that four parts of the aggregate (sand) occurs in a solution for one part of the lime. Solutions cooked on a few binders, aggregate and water are called complicatedor mixed.Composition complex solutions Eagle meaning three numbers. For example, the composition of the lime-cement solution is 1: 1: 9 indicates that one part of the lime in solution accounts for one part of the cement and nine parts of the permolor.

By destinationbuilding solutions distinguish:

masonry -for stone masonry of foundations, walls, pillars, consignments, etc.,

Fig.1. Pricing masonry

finishing -for shuttering walls, ceilings,

Fig.2. Stucco wall and ceiling

per-shit-decorative - for finishing the outer surfaces of buildings and structures,

Fig.3. Facade plaster

decorative -for finishing inside the cohesives;

Fig.4. Textured plaster

mounting - To fill and seal the seams between large elements when installing buildings and structures from the year prefabricated structures and parts;

special -wateron-permeable, acid-resistant, heat-resistant, acoustic, heat-insulating, injection, X-ray-protective and pumping and pipelines.

There are no large aggregates in the composition of solutions, therefore, in essence, they are fine-grained concrete. General patterns characterizing the properties of concrete in principle apply to solutions. However, when using solutions, two features should be taken into account. First, they were used, they are thin layers (1 ... 2 cm), without applying a mechanical seal. Secondly, solutions are often applied to porous bases (brick, concrete, light stones and blocks of porous rocks), capable of sucking the water. As a result, the properties of the solution are changed, which must be considered when determining its composition.

Selection of composition, preparation and transportation of solutions

The compositions of mortar mixtures are chosen or selected in the inspence of the prescription of the solution, the required brand and moving and the conditions for the production of work. The selected composition of RAC-creative mixtures should have the necessary mobility (without bundle and water separation when laying) with minimal consumption of the binder and ensure the obtaining of the required strength in the solidified state.

Composition construction solutions We are selected according to the tables and settlement, in both cases they are specified experimentally in relation to specific materials.

The estimated experimental method of selecting the composition of malformation is based on the implementation of the preliminary calculation of the consumption of components (binder, aggregates, water and additives) on the basis of scientifically based and experimentally proven dependencies given below. It is used to select the composition of heavy masonry and assembly solutions.

The composition of the solutions of the brands 25 ... 200 is as follows.

Pre-establish an approximate number of cement (Q. c kg per 1m3 sand), necessary to obtain a solution of a given pony:

where kp - coefficient, taking into account the quality of the sand: for large sand (MK\u003e 2.5) KP - one; for the sand of the middle size (MK \u003d 2 ... 2.5) KP-0.8 and for fine sand (MK<2) КП= 0,6,..0,7.

Then determines the number of volumetric parts of the sand (IF), which comes from one volumetric part of the cement:

where - Cement density in a loose-saturated state, kg / m3. For binding grades 300 ... 500 density takes 1200 kg / m3, and for grades 150 ... 200 - 1100 kg / m3.

Consumption of inorganic plasticizerV D. (lime test in kg per 1 m3 of sand) are determined by the formula:

The minimum number of volume parts of the limestone test (ICH), which is suitable for one volumetric part of the cement and non-accompanied to obtain a preoccupative solution, are expressed by expression:

This amount of an inorganic plasticizer is approximate; It is clarified by an experimental check of the moving mixture.

The composition of the solution in parts by volume will be as follows:

cement: Lime: Sand \u003d 1: ICH: IF.

The water consumption for obtaining a solution of a given mobility depends on the composition of the solution, the type of binder and aggregate and must be used on experienced fuses. For cement-lime solutions mobility 9 ... 10 cm water consumption IN1 m3 of sand is approximately determined by the formula

where

The calculation of the composition of the solution should be preceded by the definition of activity (brand) and the average bulk density of cement, the grain composition and module of sand size, the average density of the inorganic plasticizer (lime or clay).

Preparation of solutions. Solutions are produced in the form of ready-made or dry mixtures shutable before using water.

The process of the preparation of the solution mixture consists of dosic-based source materials, loading them into the drum mixer and stirring to obtain a homogeneous mass in a periodic mixture mixers with forced stirring. The design distinguishes multiple mixers with a horizontal or vertical loans. The latter are called turbulent mixtures.

Mixer mixers with a horizontal blade shaft you are allowed by the capacity of the finished knead 30; 65; 80; 250 and 900 liters. All these mixers, with the exception of the latter - re-engine. Capacity at the finished knee of turbulent mixtures, the working bodies of which are fast-rated rotors - 65; 500 and 800 liters.

In order for the solution to have the desired properties, it is necessary to achieve homogeneity of its composition. For this, limit the minimum mixing time. The average length of the mixing cycle for heavy solutions should be at least 3 minutes. Light solutions are stirred longer. To facilitate this process, lime and clay are introduced into a solution in the form of a limestone or clay milk. Lime dough and coming clay for mixed solutions cannot be used, since in this case it is almost impossible to achieve uniformity of the mortar mixture.

For the preparation of cement solutions with inorganic plasticizers, a lime (clay) milk of such a consistency is poured into a solution of such a consistency so that it is not necessary to additionally fill water, and then fall asleep the aggregate and cement. Organic plasticizers are first stirred in a solution mixer with water for 30 ... 45 s, and then the remaining components are loaded. Solutions are usually prepared on centralized concreteral plants or mortar nodes, which ensures the production of high quality products. In winter, to obtain solutions with a positive temperature, the components of the solution - sand and water are heated to a temperature of no more than 60 ° C. Binding can not be warm.

Transportation. Mixed mixtures from plants are transported by automotive vehicles or specially equipped with transport, excluding cement milk loss, surrounding environmental pollution, atmospheric precipitation, decrease in temperature. Transportation range depends on the type of solution, the state of the road and air temperature. In order to protect the solution from supercooling and freezing in winter, the body of the machine-tires is insulated or heated by the spent gases of the movement.

At construction sites, the mortar mixture is fed to the place of use on pipes using mortar pumps.

Terms of storage of mortar mixtures depend on the type of curziness and limited to the timing of its setting. Lime solutions retain their properties for a long time (so far water is not written from them), and the water can be added to the dried limestone and mix it again. Cement solutions are necessary to use for 2 ... 4 h; Dilution with water and the second mixing of the clutched cement solutions is not allowed, as this leads to a sharp decrease in its ka-honor, that is, the fall of the solution of the solution.