Solve 1. Write the name of the K2
CO3
compound and deduce its molecular mass. C(12), O(16)
The Correct Answer and Explanation is:
Answer:
- Name of the compound: Potassium Carbonate
Chemical Formula: K₂CO₃
Molecular Mass Calculation:
- Potassium (K): 39 × 2 = 78
- Carbon (C): 12 × 1 = 12
- Oxygen (O): 16 × 3 = 48
Total Molecular Mass = 78 + 12 + 48 = 138 g/mol
Explanation
Potassium carbonate is an inorganic compound with the chemical formula K₂CO₃. It is composed of two potassium ions (K⁺) and one carbonate ion (CO₃²⁻). The carbonate ion is a polyatomic ion consisting of one carbon atom covalently bonded to three oxygen atoms. One of the oxygen atoms forms a double bond with the carbon, while the other two carry a negative charge each and are bonded via single bonds, forming a resonance-stabilized ion. This negative charge is balanced by the two positively charged potassium ions, resulting in a neutral compound overall.
The nomenclature of potassium carbonate follows the standard IUPAC naming system. “Potassium” refers to the cation K⁺, while “carbonate” refers to the anion CO₃²⁻. Since potassium is a Group 1 alkali metal and has a fixed +1 oxidation state, and carbonate is a common polyatomic anion with a −2 charge, the chemical formula must contain two potassium ions for every one carbonate ion to maintain charge neutrality, leading to the formula K₂CO₃.
To determine the molecular mass (also known as molar mass or formula weight) of potassium carbonate, we add the atomic masses of all the atoms in the formula:
- Potassium (K) has an atomic mass of 39 g/mol. Since there are two potassium atoms, their combined mass is 78 g/mol.
- Carbon (C) has an atomic mass of 12 g/mol.
- Oxygen (O) has an atomic mass of 16 g/mol, and since there are three oxygen atoms, the total oxygen mass is 48 g/mol.
Adding these together gives the molecular mass:
78 (K) + 12 (C) + 48 (O) = 138 g/mol
Potassium carbonate is a white salt, highly soluble in water, and commonly used in soaps, glass manufacturing, and as a buffering agent.
