Potassium carbonate (K2CO3) is a white, odorless powder that is commonly used in the production of soap, glass, and ceramics. It can also be used as a food additive and a buffering agent in the pharmaceutical industry.
| IUPAC name | Potassium carbonate |
| Molecular formula | K2CO3 |
| CAS number | 584-08-7 |
| Synonyms | Carbonic acid, dipotassium salt; Pearl ash; Potash; Salt of tartar; Potassium monocarbonate; Potassium acid carbonate |
| InChI | InChI=1S/CH2O3.2K/c2-1(3)4;;/h(H2,2,3,4);;/q;2*+1/p-2/fCO3.2K/q-2;m |
Potassium Carbonate Properties
Potassium Carbonate Formula
The chemical formula for potassium carbonate is K2CO3. This formula represents the exact number of atoms of each element in the compound. The formula can be used to calculate the molar mass and other properties of the compound.
Potassium Carbonate Molar Mass
K2CO3 has a molar mass of 138.21 g/mol. This means that one mole of K2CO3 contains 138.21 grams of the compound. The molar mass is important in determining the amount of a substance needed for a particular reaction or experiment. It is also used to convert between mass and moles of a substance.
Potassium Carbonate Boiling Point
K2CO3 has a relatively high boiling point of 1,620°C (2,948°F). This makes it useful in high-temperature applications such as glass and ceramic production. The boiling point is the temperature at which a substance changes from a liquid to a gas.
Potassium Carbonate Melting Point
K2CO3 has a melting point of 891°C (1,636°F). This relatively high melting point is due to the ionic nature of the compound. When heated, the ionic bonds between the potassium and carbonate ions must be broken in order for the substance to melt.
Potassium Carbonate Density g/mL
The density of K2CO3 is 2.43 g/mL at room temperature. This means that a certain volume of K2CO3 has a certain mass. The density of a substance is an important characteristic that can be used to identify the substance and to calculate the mass or volume of a substance in a given space.
Potassium Carbonate Molecular Weight
The molecular weight of K2CO3 is 138.21 g/mol. This is the mass of one mole of the compound, which is important in many chemical calculations.
Potassium Carbonate Structure
K2CO3 has an ionic structure, with a formula of K2CO3. The potassium ion (K+) and the carbonate ion (CO32-) are held together by ionic bonds. The carbonate ion is a polyatomic ion composed of one carbon atom and three oxygen atoms.
| Appearance | White crystalline powder |
| Specific gravity | 2.43 |
| Color | White |
| Odor | Odorless |
| Molar mass | 138.21 g/mol |
| Density | 2.43 g/mL |
| Melting point | 891°C (1,636°F) |
| Boiling point | 1,620°C (2,948°F) |
| Flash point | Not applicable |
| Water solubility | 112 g/100 mL at 20°C |
| Solubility | Soluble in water, glycerol, and alcohol |
| Vapor pressure | Negligible at room temperature |
| Vapor density | Not applicable |
| pKa | 10.33 |
| pH | 11.5 (10 g/L aqueous solution) |
Potassium Carbonate Safety and Hazards
K2CO3 is generally considered safe for use in industry and in household products. However, it can be irritating to the skin and eyes, and inhalation of the powder can cause respiratory irritation. Prolonged exposure to high concentrations of K2CO3 dust can cause lung damage. It is important to wear appropriate personal protective equipment when handling this compound, including gloves, goggles, and a mask. K2CO3 is not flammable or explosive, but it can react with acids to produce carbon dioxide gas, which can be dangerous in confined spaces. In case of ingestion or contact with skin or eyes, seek medical attention immediately.
| Hazard Symbols | None |
| Safety Description | Wear gloves, goggles, and a mask. Avoid prolonged skin and eye contact. Do not inhale the powder. |
| UN IDs | UN1863 |
| HS Code | 2836.40.00 |
| Hazard Class | Non-hazardous |
| Packing Group | Not applicable |
| Toxicity | Potassium carbonate is not considered toxic, but it can cause respiratory and skin irritation in high concentrations. Prolonged exposure to high concentrations of dust can cause lung damage. |
Potassium Carbonate Synthesis Methods
Various methods can synthesize K2CO3
One common method is to react potassium hydroxide with carbon dioxide gas.
To prevent the escape of carbon dioxide gas, one can carry out this reaction in a closed vessel.
Another method involves reacting potassium chloride with sodium carbonate in an aqueous solution. The resulting K2CO3 precipitates out of the solution and can be collected by filtration.
Another way to synthesize K2CO3 is to react potassium sulfate with carbon in the presence of charcoal. Historically, chemists used the Leblanc process to produce K2CO3 on an industrial scale. However, environmental concerns have made this process uncommon today because it releases sulfur dioxide gas.
One can synthesize K2CO3 from potassium bicarbonate by heating it to a high temperature, causing it to decompose into K2CO3 and carbon dioxide gas. A furnace or kiln can carry out this reaction.
Potassium Carbonate Uses
K2CO3 has a wide range of applications in various industries due to its unique properties. Some of its common uses include:
- Production of glass: Used as a flux to lower the melting point of silica and other ingredients.
- Food industry: Used as a food additive to regulate acidity and as a leavening agent in baking.
- Soap & Detergents: Also used in the manufacture of soaps and detergents as a water softener.
- Pharmaceutical industry: Used as a buffering agent in the formulation of drugs.
- Fertilizer: Also used as a fertilizer in agriculture to provide potassium to plants.
- Production of ceramics: Used as a flux to reduce the firing temperature and improve the quality of the finished product.
- Fireworks: Used in the production of fireworks to produce a purple flame.
- Batteries: Used in the production of batteries as an electrolyte.
- Textile industry: Used as a dyeing agent.
Questions:
Q: Is potassium carbonate soluble?
A: Yes, potassium carbonate is soluble in water.
Q: Is K2CO3 soluble in water?
A: Yes, K2CO3 is soluble in water. In fact, it is highly soluble and can dissolve in water to form a clear, colorless solution.
Q: How many grams of potassium carbonate are needed to make 200 ml of a 2.5 M solution?
A: To make a 2.5 M solution of K2CO3 in 200 ml of water, you would need to dissolve 33.25 grams of K2CO3 in the water.
Calculation: Molarity = moles / volume (in liters) 2.5 M = moles / 0.2 L moles = 0.5 mol mass = moles x molar mass mass = 0.5 mol x 138.21 g/mol mass = 33.25 g
Q: What is the concentration of K ions in a 0.045 M K2CO3 solution assuming complete dissociation?
A: When K2CO3 is completely dissociated in water, it forms two K+ ions and one CO3 2- ion. Therefore, the concentration of K+ ions in a 0.045 M K2CO3 solution would be twice the molarity of the K2CO3 solution, which is 0.090 M.