Search results
Results from the WOW.Com Content Network
Boiling point (°C) K b (°C⋅kg/mol) Freezing point (°C) K f (°C⋅kg/mol) Data source; Aniline: 184.3 3.69 –5.96 –5.87 K b & K f [1] Lauric acid: 298.9 44 ...
The modern commercial production of potassium carbonate is by reaction of potassium hydroxide with carbon dioxide: [3] 2 KOH + CO 2 → K 2 CO 3 + H 2 O. From the solution crystallizes the sesquihydrate K 2 CO 3 ·1.5H 2 O ("potash hydrate"). Heating this solid above 200 °C (392 °F) gives the anhydrous salt.
The term "cryoscopy" means "freezing measurement" in Greek. Freezing point depression is a colligative property, so ΔT depends only on the number of solute particles dissolved, not the nature of those particles. Cryoscopy is related to ebullioscopy, which determines the same value from the ebullioscopic constant (of boiling point elevation).
It is manufactured by treating an aqueous solution of potassium carbonate or potassium hydroxide with carbon dioxide: [1] K 2 CO 3 + CO 2 + H 2 O → 2 KHCO 3. Decomposition of the bicarbonate occurs between 100 and 120 °C (212 and 248 °F): 2 KHCO 3 → K 2 CO 3 + CO 2 + H 2 O. This reaction is employed to prepare high purity potassium carbonate.
The following chart shows the solubility of various ionic compounds in water at 1 atm pressure and room temperature (approx. 25 °C, 298.15 K). "Soluble" means the ionic compound doesn't precipitate, while "slightly soluble" and "insoluble" mean that a solid will precipitate; "slightly soluble" compounds like calcium sulfate may require heat to precipitate.
The Gmelin rare earths handbook lists 1522 °C and 1550 °C as two melting points given in the literature, the most recent reference [Handbook on the chemistry and physics of rare earths, vol.12 (1989)] is given with 1529 °C.
KOCN is prepared by heating urea with potassium carbonate at 400 °C: . 2 OC(NH 2) 2 + K 2 CO 3 → 2 KOCN + (NH 4) 2 CO 3. The reaction produces a liquid. Intermediates and impurities include biuret, cyanuric acid, and potassium allophanate (KO 2 CNHC(O)NH 2), as well as unreacted starting urea, but these species are unstable at 400 °C.
A 52% solution of potassium formate has a freezing point of −60 °C (−76 °F). [7] Potassium formate brines are sometimes used for heat transfer, despite being much more corrosive than many other liquid coolants, especially to zinc and aluminum but even to many steels, [8] though some formulations are compatible with aluminum and steels. [9]