Baking soda (sodium bicarbonate) reacts very readily with acetic acid, forming a salt (sodium acetate) and weak carbonic acid, which immediately dissociates into carbon dioxide and water. All components and reaction products are completely harmless, and the mixture saturated with gas actively foams, making pies more magnificent and forcing schoolchildren to point fingers in surprise.

CH 3 COOH + NaHCO 3 → CH 3 COONa + H 2 CO 3 H 2 CO 3 → H 2 O + CO 2

Sodium acetate is widely used not only as a food additive (E262), but also in the chemical industry - for dyeing fabrics, vulcanizing rubber, etc. - and, of course, as part of warming "salt heaters". This substance melts at a temperature of about 58 ° C and dissolves easily in water, and if then the excess moisture is evaporated from it and cooled, a supersaturated solution can be obtained, waiting only for a slight "push" in order to instantly crystallize.

This exothermic process is accompanied by the release of a large amount of energy - from 264 to 289 kJ / kg. Unlike the production of sodium acetate, this is not a chemical reaction, but a physical process, a phase transition, and it is completely reversible. It is worth heating the mixture (for example, in a water bath), the acetate will dissolve again in the remaining water, and the “heater” can be reused.

After briefly reviewing the theory, let's move on to practical exercises. Of course, a “salt heating pad” can be bought at almost any pharmacy, and ready-made sodium acetate can be bought at the first suitable chemical reagent store. But why? All the ingredients you need can be found in your own kitchen.

Take a suitable container (a saucepan is fine) and pour in the vinegar. Keep in mind that as a result, the volume will decrease somewhere by an order of magnitude - we had to prepare the acetate solution in several batches.

Carefully add the baking soda, don't rush, letting each new batch react, otherwise you really have to get acquainted with the "chemical volcano". For every 500 ml of a 9% vinegar solution, we used 4-5 teaspoons of baking soda.

We got an acetate solution, from which it remains to evaporate the excess water. Put the pan on low heat and make sure that the liquid boils slowly until small crystals of acetate begin to appear on the walls. The solution then turns yellowish and decreases in volume by almost 90% - this can take an hour or more.

While our solution was evaporating, we made an activator for the heating pad: we took out the base, a curved metal ribbon, from the ruler bracelet, and cut out a circle from it, which, when pressed, bends either in one direction or the other with a click. So that such a “button” does not damage the heating pad, it was tightened with electrical tape.

Warming "volcano"

We poured the oversaturated acetate solution into a heating pad, putting our activator in it - but in principle, the reaction can be started without it. It is enough to throw inside one of the crystals that remained on the walls of the dishes, and once spontaneous crystallization began with us simply from a sharp blow. The heat in such a heating pad can last up to several hours, and for reuse it is enough to heat it in a water bath, again converting the acetate into a liquid form.

The article "Home-made heat, do-it-yourself chemical heating pad" was published in the journal "Popular Mechanics" (

With the cold, when you are in natural conditions far from home, you can and should fight. Moreover, now there are many modern and technologically advanced portable devices on the market, individual heaters of various types and types, compact gas heaters, and so on, the operation of which is based on various physical and chemical processes.

According to statistics, from 10 to 15% of people who died in natural conditions became victims. Even the warmest clothes, at negative air temperatures, are able to maintain a positive thermal balance of the human body only for a very limited time. Sooner or later, the heat loss will be greater than the heat production and the cooling of the body will begin. Prolonged exposure to cold is dangerous. It paralyzes the will and dulls the instinct of self-preservation. This can eventually lead to at least serious health problems, or at most to death.

Disposable chemical heating pads and thermal packs for heating in the field.

The cheapest and most affordable means of individual heating are various disposable chemical heating pads (thermal packs) for hands and feet. Heat in such heating pads is usually generated as a result of a chemical reaction between the contents of the package itself and oxygen. Such heating pads are very easy to use, sometimes it will be enough to start the process of heat release by removing it from the package. The operating temperature, depending on the purpose of the disposable heating pad, is from plus 40 to 60 degrees Celsius. Operating time - from 4 hours or more.

The design of some disposable chemical heaters allows you to temporarily stop the process of heat release from it. To do this, it is enough to stop the access of oxygen to its active content and the reaction stops. Disposable chemical heating pads will be convenient autonomous sources of heat for fishermen, tourists, hunters and the military. They can be put in shoes, in gloves, in inner pockets of clothes, to heat equipment (photo and video cameras) when working in the cold, etc.

Reusable salt heaters for heating in the field.

Reusable salt heaters is a sealed container made of dense material, which is filled with a supersaturated saline solution. The principle of operation is based on the effect of heat release when the phase state of materials changes. Salt heating pad can have almost any shape and size. So, for example, a saline foot warmer can be in the form of an insole.

Inside the heater there is an applicator (stick or circle), with the help of which it is launched. The operating temperature of salt heaters is from 50 degrees and above. The operating time depends on the size of the heater itself and the ambient temperature - from 2 hours or more. After the end of the work cycle, salt heaters are put into working condition by placing them in boiling water for a while, after which it is again ready for reuse.

Reusable catalytic heaters for heating in the field.

In addition to disposable chemical heaters, there are reusable pocket catalytic heaters. The principle of their operation is based on the catalytic flameless oxidation of alcohol or gasoline vapors, which is accompanied by the release of heat. Platinum serves as a catalyst in such heating pads. A prime example is the classic Zippo Hand Warmer. More details about it are written on our website.

Prevention of hypothermia in cold weather.

In cold weather, you should try to adhere to the following simple rules.

1. Generate heat.

Eat often, but little by little, and high-calorie foods. When food is taken frequently and in small portions, this increases the overall metabolic rate of the body, since more calories are consumed in the process of digestion. This in turn leads to the production of more internal heat.

If necessary.

- Do warm-up exercises.
- Make fire and use reflective surfaces.
- If possible, always be located on the south side in order to receive maximum solar heat.
- Drink warm or hot liquids with sweets or sugar dissolved in them.

2. Reduce heat loss.

- Wear appropriate clothing and footwear for the weather.
- Especially insulate the head and neck.
- As soon as possible, immediately change from wet clothes to dry.
- Find or make a protective cover or shelter.
– Isolate the body from cold surfaces as much as possible.
- Avoid alcohol completely.

• Do not put the heating pad in the microwave
• When restoring the heating pad, always use a cloth or towel.
• When removing the heating pad from boiling water, avoid sharp objects.
• If after use the heating pad is in a solid state, do not attempt to fold it to place it in a saucepan, this may cause the package to burst. First boil one side of the heating pad, then turn over and boil the other side so that it becomes soft, and then you can completely lower the heating pad into the pan.
• When punctured, the heating pad self-crystallizes and becomes unusable.
• When the heating pad is cooled down to - 8 Cº, the solution self-crystallizes. To restore the heating pad, it must first be warmed to room temperature, and then boiled.
• If the heating pad you purchased is in a solid state, it means that it has self-crystallized due to accidental strong. shock or low temperature during transportation. This is a natural phenomenon - if it occurs, then boil the heating pad before the first use.
• To warm the body for people with sensitive skin and children under 3 years old, it is recommended to wrap the heating pad with a cloth.
• During the operation of the heating pad, crystals in the form of snowflakes may appear in the solution. The presence of crystals does not affect the normal operation of the heater and is not a defect of the salt heater.
• The insole warmers are not designed to be used as walking insoles. The maximum static load on the heaters must not exceed 90 kg.
• In case of contact with the solution on the mucous membranes of the eyes, nose, mouth, rinse them with warm water.
• Store at room temperature. Avoid direct sunlight.
• Before using a salt heating pad for medicinal purposes, consult a specialist.

When hiking, fishing, especially in bad weather, there is often a need for an ordinary heating pad. Of course, ordinary rubber is also good, but it has one significant drawback: water is heated very slowly for it at the stake. Let's try to make a chemical heating pad. To do this, we need the most common reagents.

When hiking, fishing, especially in bad weather, there is often a need for an ordinary heating pad. Of course, ordinary rubber is also good, but it has one significant drawback: water is heated very slowly for it at the stake.

Let's try to make a chemical heating pad. To do this, we need the most common reagents.

Let's start with a simple experiment. Go to the kitchen and take a pack of table salt. However, you don't need a pack. 20 g (2 teaspoons) will be enough. Then look into the locker, where all kinds of household preparations and materials are stored. Surely there was preserved after the repair of the apartment a little copper sulphate. It will need 40 g (3 teaspoons). Wood chips and a piece of aluminum wire, presumably, will also be found. If so, you're all set. Pound vitriol and salt in a mortar so that the size of the crystals does not exceed 1 mm (of course, by eye). Add 30 g (5 tablespoons) of sawdust to the resulting mixture and mix thoroughly. Bend a piece of wire with a spiral or snake, put it in a mayonnaise jar. Pour the prepared mixture there so that the backfill level is 1-1.5 cm below the neck of the jar. The heating pad is in your hands. To put it into action, it is enough to pour 50 ml (a quarter cup) of water into a jar. After 3-4 minutes, the temperature of the heating pad will rise to 50-60°C.

Where does the heat come from in the jar, and what role does each of the components play? Let's look at the reaction equation:

CuSO4+2NaCl Na2SO4+CuCl2

As a result of the interaction of copper sulfate with common salt, sodium sulfate and copper chloride are formed. It is she who interests us. If we calculate the heat balance of the reaction, it turns out that the formation of one gram-molecule of copper chloride releases 4700 calories of heat. Plus, the heat of dissolution in the initial resulting preparations is 24999 calories. Total: Approximately 29,600 calories.

Immediately after formation, copper chloride interacts with aluminum wire:

2Al+3CuCl2 2AlCl3+3Cu

In this case, approximately 84,000 calories are released (also in terms of 1 g-mol of copper chloride).

As you can see, as a result of the process, the total amount of heat released exceeds 100,000 calories per gram-molecule of the substance. So there is no mistake or deceit: the heating pad is real.

What about sawdust? Not taking any part in chemical reactions, they at the same time play a very important role. Greedily absorbing water, sawdust slows down the course of reactions, stretches the work of the heating pad in time. In addition, wood has a fairly low thermal conductivity: it kind of accumulates the released heat and then constantly gives it away. In a tightly sealed container, heat is retained for at least two hours.

And the last remark: the bank, of course, is not the best vessel for a heating pad. We only needed it for demonstration purposes. So think for yourself about the shape and material for the tank in which to place the heating mixture.

When hiking, fishing, especially in bad weather, there is often a need for an ordinary heating pad.

When hiking, fishing, especially in bad weather, there is often a need for an ordinary heating pad. Of course, ordinary rubber is also good, but it has one significant drawback: water is heated very slowly for it at the stake. Let's try to make a chemical heating pad. To do this, we need the most common reagents.

When hiking, fishing, especially in bad weather, there is often a need for an ordinary heating pad. Of course, ordinary rubber is also good, but it has one significant drawback: water is heated very slowly for it at the stake.

Let's try to make a chemical heating pad. To do this, we need the most common reagents.

Let's start with a simple experiment. Go to the kitchen and take a pack of table salt. However, you don't need a pack. 20 g (2 teaspoons) will be enough. Then look into the locker, where all kinds of household preparations and materials are stored. Surely there was preserved after the repair of the apartment a little copper sulphate. It will need 40 g (3 teaspoons). Wood chips and a piece of aluminum wire, presumably, will also be found. If so, you're all set. Pound vitriol and salt in a mortar so that the size of the crystals does not exceed 1 mm (of course, by eye). Add 30 g (5 tablespoons) of sawdust to the resulting mixture and mix thoroughly. Bend a piece of wire with a spiral or snake, put it in a mayonnaise jar. Pour the prepared mixture there so that the backfill level is 1-1.5 cm below the neck of the jar. The heating pad is in your hands. To put it into action, it is enough to pour 50 ml (a quarter cup) of water into a jar. After 3-4 minutes, the temperature of the heating pad will rise to 50-60°C.

Where does the heat come from in the jar, and what role does each of the components play? Let's look at the reaction equation:

CuSO4+2NaCl > Na2SO4+CuCl2

As a result of the interaction of copper sulfate with common salt, sodium sulfate and copper chloride are formed. It is she who interests us. If we calculate the heat balance of the reaction, it turns out that the formation of one gram-molecule of copper chloride releases 4700 calories of heat. Plus, the heat of dissolution in the initial resulting preparations is 24,999 calories. Total: Approximately 29,600 calories.

Immediately after formation, copper chloride interacts with aluminum wire:

2Al+3CuCl2 > 2AlCl3+3Cu

In this case, approximately 84,000 calories are released (also in terms of 1 g-mol of copper chloride).

As you can see, as a result of the process, the total amount of heat released exceeds 100,000 calories per gram-molecule of the substance. So there is no mistake or deceit: the heating pad is real.

What about sawdust? Not taking any part in chemical reactions, they at the same time play a very important role. Greedily absorbing water, sawdust slows down the course of reactions, stretches the work of the heating pad in time. In addition, wood has a fairly low thermal conductivity: it kind of accumulates the released heat and then constantly gives it away. In a tightly sealed container, heat is retained for at least two hours.

And the last remark: the bank, of course, is not the best vessel for a heating pad. We only needed it for demonstration purposes. So think for yourself about the shape and material for the tank in which to place the heating mixture.