CN111243409A - Demonstration component of color-changing reagent and color-changing demonstration method - Google Patents

Abstract

The invention discloses a discoloration reagent demonstration component and a discoloration demonstration method, comprising a set of discolorable reagents, qualitative filter paper, reagent bottles and matching paintbrushes; wherein the discolorable reagent is mixed with a main discoloration agent A and an additive B to form a color-changing reagent. Among them, the main color-changing reagent includes five kinds of color-changing reagents, namely AgNO ₃ solution, K ₂ CrO ₄ solution, KSCN solution, KI solution and Na ₂ S solution. The chemical reaction sequence of B is painted on the qualitative filter paper in turn; the additive B is polyvinyl alcohol solution. Applying the demonstration component of the present invention, the qualitative filter paper (usually white qualitative filter paper) can intuitively show obvious color changes, and in the process of painting, it does not sag and can immediately develop and change color. In the teaching process Stimulate students' curiosity and thirst for knowledge. It can also be combined with existing teaching methods such as projection.

Description

A demonstration component of a color-changing reagent and a method for color-changing demonstration

technical field

The invention relates to the field of teaching demonstration, in particular, to a demonstration component of a color-changing reagent and a method for color-changing demonstration.

Background technique

At present, under the premise of quality teaching, in order to stimulate students' interest in chemical reaction knowledge, guide them to think, and further mobilize students' enthusiasm, it has always been the task and goal of teaching. For this reason, we explore and invent a new demonstration method. and method. The conventional method is generally selected in a transparent test tube or container, through one or two discoloration, to improve students' attention or enthusiasm. However, because the test-tube demonstration is a kind of cognition in a normal learning situation, it cannot fully stimulate the curiosity of students, and the test-tube demonstration increases the consumption of reagents and needs to be operated in a fixed environment, which is not conducive to carrying; not only that, conventional Test tube color development is not easy to combine with modern teaching aids such as projection, and cannot be adapted to modern teaching methods.

SUMMARY OF THE INVENTION

The purpose of the present invention is to organically combine painting activities with chemical reaction discoloration phenomenon, and overcome the disadvantages of large consumption of traditional experimental reagents, fixed operating environment and inability to adapt to advanced teaching aids such as projection, etc., and provide a demonstration of color-changing reagents A method of components and color-changing presentations that provide a mobile and ubiquitous approach to learning. Applying the demonstration component of the present invention, the filter paper (usually white filter paper) can intuitively show obvious color change, and during the painting process, it does not sag and can immediately develop and change color. The conventional three-primary principle of pigment superimposed discoloration is different. In this experiment, there will be discoloration between colorless and colorless coatings, and between colored and colorless coatings, which can fully arouse students' curiosity and desire for knowledge in the teaching process. Not only that, the present invention paints or paints on the filter paper, the color rendering area is larger and more intuitive, and at the same time, it can be combined with the existing teaching means such as projection. In addition, the chemical reagent used in the present invention is small, which saves more reagents than conventional test tube color development demonstration, and has the advantages of convenient portability and optional operation environment.

In order to achieve the above purpose, the present invention provides a demonstration component of a color-changing reagent, including a set of color-changing reagents, qualitative filter paper and reagent bottle matching pen; ; wherein, the main color-changing agent A includes a total of five color-changing reagents, which are respectively one in AgNO ₃ solution, K ₂ CrO ₄ solution, KSCN solution, KI solution and Na ₂ S solution; The predetermined chemical reaction sequence is brushed and overlaid on the qualitative filter paper in turn; the additive B is a polyethylene solution.

The present invention also provides a method for color-changing demonstration using the demonstration component described above, which includes firstly coating the color-changing reagent containing AgNO ₃ solution on qualitative filter paper, and then coating the color-changing reagent containing K ₂ CrO ₄ solution on the qualitative filter paper. Color-changing reagent, brick-red color appears at the overlap of two color-changing reagents, and then the color-changing reagent containing KSCN solution is applied to the brick-red color, and the brick-red turns to white; The place turned yellow; then the yellow place was coated with Na ₂ S solution, and the yellow place turned black.

Through the above technical scheme, the present invention can paint the color-changing reagent on the qualitative filter paper according to the predetermined chemical reaction sequence. In the above technical solution, the predetermined chemical reaction can be 2Ag ⁺ +CrO ₄ ^2- =Ag ₂ CrO ₄ ↓ (brick red), Ag ₂ CrO ₄ +CN ^- =AgSCN↓ (white); AgSCN+I ^- =AgI ↓ (yellow); AgI+S ^2- =Ag ₂ S↓ (black), that is, first coat the color-changing reagent containing AgNO ₃ solution on the qualitative filter paper, and then coat the color-changing reagent containing K ₂ CrO ₄ solution Reagent, brick red appears at the overlap of the two color-changing reagents, and then the color-changing reagent containing KSCN solution is applied to the brick-red color, and the brick-red turns to white; then the color-changing reagent containing KI solution is used to coat the white place, and the white place changes. It is yellow; the yellow part is then coated with Na ₂ S solution, and the yellow part turns into black. In this way, four color changes can appear on the filter paper with the superposition of the reagents. Not only that, applying the demonstration component of the present invention can intuitively display obvious color changes on the filter paper (usually white filter paper), and during the painting process, it does not sag and can immediately develop and change color. The present invention provides The discoloration of the paint is different from the superimposed discoloration of the conventional three-primary color principle. This phenomenon will appear discoloration between colorless and colorless coatings, and between colored and colorless coatings. It can organically combine the painting process with the chemical reaction phenomenon, so that it can Arouse students' curiosity and thirst for knowledge in the teaching process. Not only that, the present invention paints or paints on the filter paper, the color developing area is larger and more intuitive, and it can also be combined with the existing teaching means such as projection. Not only that, the chemical reagents used in the present invention are small, and compared with conventional test tube color development demonstrations, it saves more reagents, is easy to carry, and realizes mobile and ubiquitous learning effects.

Other features and advantages of the present invention will be described in detail in the detailed description that follows.

Description of drawings

The accompanying drawings are used to provide a further understanding of the present invention, and constitute a part of the specification, and are used to explain the present invention together with the following specific embodiments, but do not constitute a limitation to the present invention. In the attached image:

Figure 1 is a side view of a demonstration assembly of a color-changing reagent.

In Figure 1: 1 is the qualitative filter paper; 2 is the foil layer.

Figure 2 is a schematic structural diagram of a reagent bottle matching pen arrangement.

In Figure 2: 3 is a reagent bottle; 4 is a bottle cap; 5 is a row of pens.

Detailed ways

Specific embodiments of the present invention will be described in detail below. It should be understood that the specific embodiments described herein are only used to illustrate and explain the present invention, but not to limit the present invention.

The endpoints of the ranges disclosed herein and any values are not limited to the precise ranges or values, which are to be understood to include values near those ranges or values. For ranges of values, the endpoints of each range, the endpoints of each range and the individual point values, and the individual point values can be combined with each other to yield one or more new ranges of values that Ranges should be considered as specifically disclosed herein.

The present invention provides a demonstration component of a color-changing reagent, which includes a set of color-changing reagents, qualitative filter paper, reagent bottles and matching pens; wherein, the color-changing reagent is mixed with a main color-changing agent A and an additive B; The group of color-changing reagents includes a total of five color-changing reagents, and the main color-changing agent A is AgNO ₃ solution, K ₂ CrO ₄ solution, KSCN solution, KI solution and Na ₂ S solution. The predetermined chemical reaction sequence is brushed and overlaid on the qualitative filter paper in turn; the additive B is a polyvinyl alcohol solution. In this way, when using, the color-changing reagent can be painted on the qualitative filter paper according to the predetermined chemical reaction sequence, and under the predetermined chemical reaction, the color will develop on the filter paper, and with the superposition of the reagents, the color will appear. In the above technical solution, the predetermined chemical reaction can be 2Ag ⁺ +CrO ₄ ^2- =Ag ₂ CrO ₄ ↓ (brick red), Ag ₂ CrO ₄ +CN ^- =AgSCN↓ (white); AgSCN+I ^- =AgI ↓ (yellow); AgI+S ^2- =Ag ₂ S↓ (black), that is, first coat the color-changing reagent containing AgNO ₃ solution on the qualitative filter paper, and then coat the color-changing reagent containing K ₂ CrO ₄ solution Reagent, brick-red color appears at the overlapping of two color-changing reagents, and then the color-changing reagent containing KSCN solution is applied to the brick-red color, and the brick-red turns to white; and then the color-changing reagent containing KI solution is used to coat the white place, and the white place changes. It is yellow; the yellow part is then coated with Na ₂ S solution, and the yellow part turns into black. In this way, four color changes can appear on the filter paper with the superposition of the reagents. Not only that, applying the demonstration component of the present invention can intuitively show obvious color change on the filter paper (usually white filter paper), and during the painting process, it does not sag and can immediately develop and change color. The present invention provides The color change is different from the superimposed color change of the conventional three-primary color principle. It has the discoloration between colorless and colorless coatings, and the color change characteristics between colored and colorless coatings, etc., which can arouse students' curiosity and knowledge in the teaching process. want. Not only that, the present invention paints or paints on the filter paper, the color development area is larger and more intuitive, and it can also be combined with existing teaching methods such as projection. Not only that, the chemical reagents used in the present invention are small, and compared with conventional test tube color development demonstration, it saves more reagents, is convenient to carry, easy to operate, and can realize mobile and ubiquitous learning effects.

In a preferred embodiment of the present invention, the concentration of the main color-changing agent A is 0.08-0.12 mol/L; the volume ratio of the main color-changing agent A and the additive B is 1:0.8-1.2; the mass fraction of the additive B is 1% -2% solution of polyvinyl alcohol (degree of polymerization 1700-1800). In this way, each reaction can be made more intuitive, and during the demonstration process, the color change is fast and more obvious without sagging.

In a preferred embodiment of the present invention, as shown in FIG. 1 , it further includes a backing layer 2 disposed below the qualitative filter paper 1 . Preferably, the backing layer is corrugated paper.

In a preferred embodiment of the present invention, the qualitative filter paper is a medium-speed qualitative filter paper. Preferably, the qualitative filter paper is a thickened qualitative filter paper on the market, so that more main color-changing agents can be adsorbed, so that the color change is fast and obvious for the subsequent reaction.

In a preferred embodiment of the present invention, the backside of the qualitative filter paper is attached to the backing layer by coating the backside of the qualitative filter paper with solid glue.

In a preferred embodiment of the present invention, it also includes the step of storing the reagent in a brown or dark reagent bottle with a seamless matching row of pen caps before applying the color-changing reagent.

In a preferred embodiment of the present invention, as shown in FIG. 2 , the bottle cap 4 can be screwed on the reagent bottle 3 by inserting the row of pens 5 into the bottle cap 4 .

The present invention also provides a method for color-changing demonstration using the demonstration component described above, which includes firstly coating the color-changing reagent containing AgNO ₃ solution on qualitative filter paper, and then coating the color-changing reagent containing K ₂ CrO ₄ solution on the qualitative filter paper. Color-changing reagent, brick-red color appears at the overlap of two color-changing reagents, and then the color-changing reagent containing KSCN solution is applied to the brick-red color, and the brick-red turns to white; The place turned yellow; then the yellow place was coated with Na ₂ S solution, and the yellow place turned black.

The method of the invention has the advantages of more color development and discoloration, fast and obvious discoloration, and painting on filter paper is like conventional painting, but the discoloration is different from the color development of conventional three-primary color pigments, which makes the process more surprising, and can improve the students' learning ability. Curiosity and thirst for knowledge.

The color changes in turn: brick red→white→yellow→black, you can also jump along the brick red→black direction and add reagent coating, jumping color change, but can not reverse coating color change, such as from brick red to yellow, in In the order of brick red to yellow in front, KSCN can be used without coating, or brick red to black, yellow to black, etc., but not from black to yellow, or from yellow to brick red, etc.

In a preferred embodiment of the present invention, it also includes the step of attaching a backing layer to the back of the qualitative filter paper before applying the color-changing reagent.

The present invention will be described in detail below by means of examples.

Preparation Example 1

Preparation of reagents:

Preparation of main color-changing agent A: AgNO ₃ solution, K ₂ CrO ₄ solution, KSCN solution, KI solution and Na ₂ S solution with concentrations of 0.08 mol/L were prepared respectively.

Formulating additive B: Formulating a solution containing 1% by mass of polyvinyl alcohol (polymerization degree 1799).

The prepared AgNO ₃ solution, K ₂ CrO ₄ solution, KSCN solution, KI solution and Na ₂ S solution were mixed with additive B in a volume ratio of 1:1.2, respectively, to obtain a set of color-changing reagents.

Preparation Example 2

Preparation of reagents:

Preparation of main color-changing agent A: respectively prepare AgNO ₃ solution, K ₂ CrO ₄ solution, KSCN solution, KI solution and Na ₂ S solution with concentrations of 0.10 mol/L.

Preparation of additive B: A solution containing polyvinyl alcohol (polymerization degree 1799) with a mass fraction of 1.5% was prepared.

The prepared AgNO ₃ solution, K ₂ CrO ₄ solution, KSCN solution, KI solution and Na ₂ S solution were mixed with additive B in a volume ratio of 1:1, respectively, to obtain a set of color-changing reagents.

Preparation Example 3

Preparation of reagents:

Preparation of main color-changing agent A: AgNO ₃ solution, K ₂ CrO ₄ solution, KSCN solution, KI solution and Na ₂ S solution with concentrations of 0.12 mol/L were prepared respectively.

Preparation of additive B: A solution containing 2% by mass of polyvinyl alcohol (polymerization degree 1799) was prepared.

The prepared AgNO ₃ solution, KSCN solution, K ₂ CrO ₄ solution, KI solution and Na ₂ S solution were mixed with additive B in a volume ratio of 1:0.8, respectively, to obtain a set of color-changing reagents.

Example 1

The drawing paper is an ordinary medium-speed qualitative filter paper. One side of the filter paper is coated with solid glue, and the other side of the filter paper is a picture.

Take a group of color-changing reagents in Preparation Example 1, first coat the color-changing reagent containing AgNO ₃ solution on the qualitative filter paper, and then coat the color-changing reagent containing K ₂ CrO ₄ solution. Brick red appears, and then apply the color-changing reagent containing KSCN solution to the brick red, and the brick red turns into white; then use the color-changing reagent containing KI solution to coat the white part, and the white part turns yellow; and then use Na ₂ S The solution coats the yellow spots, which turn to black.

Its precipitation transformation reaction is:

2Ag ⁺ +CrO ₄ ^2- =Ag ₂ CrO ₄ ↓ (brick red)

Ag ₂ CrO ₄ +SCN ^- =AgSCN↓ (white)

AgSCN+I ^- =AgI↓ (yellow)

AgI+S ^2- =Ag ₂ S↓ (black)

The color changes in turn: brick red→white→yellow→black, you can also jump and add reagent coating along the direction of brick red→black, and the color will change by jumping, but you cannot reverse the color change, such as from brick red to yellow, in the front No KSCN coating is required in the order of brick red to yellow, but not from black to yellow, or from yellow to brick red, etc.

Example 2

Take a group of color-changing reagents in Preparation Example 2 and paint on filter paper according to the method of Example 1.

Example 3

Take a group of color-changing reagents in Preparation Example 3 and paint on filter paper according to the method of Example 1.

Comparative Example 1

Only the main color-changing agent A in the preparation example was used as the color-changing agent, that is, no additive B was added, and the filter paper was painted according to the method of Example 1.

Table 1

Example number Phenomenon Example 1 Fast color development, obvious color change and no sagging Example 2 Fast color development, obvious color change and no sagging Example 3 Fast color development, obvious color change and no sagging Comparative Example 1 Color development is slow, uneven, and sags

The preferred embodiments of the present invention are described in detail above, but the present invention is not limited to the specific details of the above-mentioned embodiments. Within the scope of the technical concept of the present invention, various simple modifications can be made to the technical solutions of the present invention. These simple modifications All belong to the protection scope of the present invention.

In addition, it should be noted that the specific technical features described in the above-mentioned specific embodiments can be combined in any suitable manner unless they are inconsistent. In order to avoid unnecessary repetition, the present invention provides The combination method will not be specified otherwise.

In addition, the various embodiments of the present invention can also be combined arbitrarily, as long as they do not violate the spirit of the present invention, they should also be regarded as the contents disclosed in the present invention.

Claims (10)

1. A demonstration component of a color-changing reagent is characterized by comprising a group of color-changing reagents, qualitative filter paper, reagent bottles and matched row pens;

wherein, the color-changing reagent is formed by mixing a main color-changing agent A and an additive B; wherein the main color changing agent A is a group of five color changing agents which are AgNO₃Solution, K₂CrO₄Solution, KSCN solution, KI solution and Na₂(ii) one of S solutions;

and the color-changeable reagent can be sequentially coated on the qualitative filter paper according to a set chemical reaction sequence;

the additive B is polyvinyl alcohol solution.

2. The demonstration assembly according to claim 1, wherein the concentration of the primary colorant a is 0.08-0.12 mol/L.

3. The demonstration assembly according to claim 2, wherein each of the variable color agents in the primary colorant a is mixed with the additive B in a volume ratio of 1: 0.8-1.2.

4. The demonstration assembly according to claim 3, wherein the additive B comprises a polyvinyl alcohol solution with a mass fraction of 1% -2%; the polymerization degree of the polyvinyl alcohol is 1700-1800.

5. The demonstration assembly according to claim 4, further comprising a backing layer disposed below the qualitative filter paper; wherein, the backing layer is corrugated paper.

And/or the qualitative filter paper is medium-speed qualitative filter paper.

6. The demonstration assembly according to any of claims 1 to 5, wherein the row of pens is inserted in the middle of the cap of the bottle, and the row of pens and the cap of the bottle are seamlessly joined.

7. The demonstration assembly of claim 6, wherein the reagent bottle is a twist-top brown glass bottle or a dark plastic bottle.

8. A method of demonstrating color change using the demonstration assembly of any one of claims 1 to 7, comprising first including AgNO₃The solution color-changing reagent is coated on qualitative filter paper, and then coated with K₂CrO₄The color-changing reagent of the solution, brick red appears at the overlapped position of the two color-changing reagents, and then the brick red is coated on the brick red position by the color-changing reagent containing the KSCN solution, so that the brick red is changed into white; coating the white part with a color-changing reagent containing KI solution, and changing the white partIs yellow; further using Na₂The S solution coats the yellow spot which turns to black.

9. The method of claim 8, further comprising the step of attaching a backing layer to the back side of the qualitative filter paper before applying the color-changing reagent.

10. The method of claim 9, wherein the back side of the qualitative filter paper is attached to the susceptor by coating the back side of the qualitative filter paper with a solid glue.

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