Flame reaction related to potassium, flame reaction of potassium

The main purpose of observing with blue cobalt glass is to exclude the interference of sodium, that is, to exclude yellow, for other color interference, because in general, most of the impurities contained in potassium and potassium-containing compounds are substances containing sodium, and only a small part are other elements, so their influence is not considered.

Let's start with two concepts:

1. The concept of complementary color: the same amount of two colors is mixed to show black or gray, then these two colors are complementary to each other, of which purple is yellow, blue is orange;

2. The colors we usually see are actually complementary colors of absorbed colors, for example, leaves are green, that is because chlorophyll mainly absorbs red and blue light (red accounts for the majority), when sunlight hits the surface of leaves, a large amount of red is absorbed, and only the complementary green is reflected back, so what we see is green, and the principle of color development of flowers of various colors is also like this, and the light of complementary colors is absorbed.

When observing the color of potassium in the flame color reaction, because potassium-containing substances usually have sodium, and the yellow color of sodium has a great interference with the purple color of potassium (they just complement each other), so we must use the blue glass that can absorb the orange-yellow color to absorb the yellow color of sodium, so that we can see the purple color of potassium.

Yellow and blue are complementary colors, and blue cobalt glass is blue because it absorbs yellow light, so the function of blue cobalt glass is to remove yellow to facilitate the sighting of very light purple.

You're right, if you look at red through blue cobalt glass, you will see purple, and purple at this time is actually a superposition of red and blue, because red is not absorbed, and it is different from the previous color production principle.

Flame color reaction of potassium:

It is a solution containing potassium ions that is dipped in a metal wire such as a tested iron wire and burned on a flame. The reaction is mainly to observe the color of the flame during combustion, in which the flame color reaction of potassium is light purple, and there is a method in chemistry to identify the metal ions contained in the unknown solution through the flame color reaction, because the color produced by the flame color reaction of different metal ions is different.

Role of potassium:

1. Lower blood pressure and protect heart health.

Diets with high sodium levels can raise blood pressure, especially for those who already have high blood pressure, and a diet rich in potassium will help the body remove excess sodium to lower blood pressure. Potassium also plays a protective role in heart health, because potassium combined with minerals such as calcium and magnesium prevents fluid from accumulating in cells, which can raise blood pressure, leading to heart palpitations, narrowing of arteries, scarring or poor circulation.

2. Regulate muscle contraction and prevent muscle spasm and pain.

The nervous system helps regulate muscle contractions, and when blood potassium levels are low, it weakens nerve signals, resulting in reduced muscle contractions. That's why many athletes eat bananas to replenish potassium before they go on the field, because they sweat more and lose more potassium.

3. Support the nervous system, improve fatigue and poor concentration.

The nervous system is responsible for transmitting information between the brain and the body, which is transmitted in the form of "nerve impulses", which are produced by sodium leaving the combustion hole into the cell and potassium ions moving out of the cell. Therefore, if you get enough potassium from your diet, you can help maintain a healthy nervous system, which can improve your concentration and learning ability, and reduce fatigue.

The flame color reaction of potassium is purple. The flame color reaction of potassium chloride is purple. Potassium is a white solid, which can be integrated into water, and is also an essential electrolyte for the human body, an indispensable substance to maintain human life.

What is the flame color reaction

The flame reaction is actually a physical change, which is a change in the energy level of electrons inside the atoms of matter. In layman's terms, a flame reaction is a change in the energy of an electron in an atom and does not involve a change in the structure and chemical properties of matter. Some metals, or their compounds, can give the flame a special color when burned, because the atoms of these metallic elements jump from a lower energy orbital to a higher energy orbital when they receive the energy provided by the flame.

The flame color reaction, also known as the flame color test and the flame color test, is a reaction that causes the flame to take on its characteristic color when certain metals or their compounds are burned in a colorless flame. The principle is that each element has its own individual spectrum.

Method 1 (beaker alcohol method):

Take a small spoon of anhydrous potassium carbonate powder (fully grind) and put it on an inverted small beaker, add 5 to 6 drops of alcohol, ignite, you can see a clear light purple flame, if you look at it through a piece of cobalt glass, you can see the purple flame more obviously.

2) Method 2 (wire method):

The student experimental method in the second method of the same sodium. This method is not as effective as the method.

One, two, three, but close to the textbook approach.

When observing the potassium flame color, the indoor light should not be too strong, otherwise the light purple potassium flame is not obvious, if you want to avoid the influence of sodium salt on the observation of potassium salt, you should observe the flame color through blue cobalt glass.

Contains sodium ions Na yellow.

Contains lithium-ion lichen red.

Potassium ion K light violet (through blue cobalt glass).

Contains rubidium ions RB violet.

Ca-containing ca-brick red.

Contains strontium ion SR magenta.

Contains copper ions cu green.

Contains barium ions BA yellow-green.

Contains cesium ion CS purple red.

Fe containing iron ions is colorless.

Windshield clips prevent flame color interference.

For commonly used models of alcohol lamps, take a thin iron sheet of 14 size, fold it twice, and turn it into a windshield clip with a length and width and a height of 14cm. Bend the lower end slightly and clip it to the alcohol lamp when in use, as shown in the picture on the right. Then take a few rust-free wires and fix them on the glass rod and mark them.

Each wire is dedicated to taking one sample. This is used as an alternative to platinum wire (due to constraints, many schools do not have as much platinum wire, especially when working in groups).

Simplified operating procedures.

When demonstrating the experiment in class, face the empty side of the windshield on the alcohol lamp toward the students. Dip the corresponding sample with a special wire. It is possible not to "burn first......Wash the ...... with dilute hydrochloric acid after each use"And it is directly placed on the outer flame part of the burning.

When demonstrating the flame reaction of potassium, a small amount of synthetic glue can be dipped in iron wire, and then a small amount of potassium chlorate solid can be "glued" directly burned, and the cobalt slide can be placed in the vacant part of the windshield clamp for observation, and the experiment can be repeated after the wire is slightly cooled. This method can also be used for other methods that are easily disturbed by external conditions and the flame color display is not obvious. At the end of the experiment, remove the windshield clip and turn off the alcohol lamp.

Improved advantages.

By adding a wind clip, the flame of the alcohol lamp can not only be prevented from being disturbed by the wind during the experiment, but also effectively increase the length of the flame without blocking the students' vision, and can also form a background color, which is conducive to comparative observation. Switching to a special wire to dip the sample solves the problem of missing platinum wire and simplifies the operation. The use of synthetic glue to "stick" the solid sample for burning will not only not affect the observation of the flame color, but also effectively prevent the sample from splashing and prolong the flame color time, which is simple and practical.