Consider the compound potassium hypochlorite. a. Write out the formula for potassium hypochlorite. b. Determine the molecular weight (molar mass) of potassium hypochlorite. c. Calculate the number of moles of potassium hypochlorite in 78.54 grams of the compound. d. Calculate the total number of atoms of oxygen in 78.54 grams of potassium hypochlorite.
The correct answer and explanation is :
Potassium hypochlorite is an inorganic compound with the chemical formula KClO. It consists of potassium (K⁺) and hypochlorite (ClO⁻) ions.
a. Chemical Formula of Potassium Hypochlorite:
The chemical formula for potassium hypochlorite is KClO. This indicates that each formula unit comprises one potassium atom (K), one chlorine atom (Cl), and one oxygen atom (O).
b. Molar Mass of Potassium Hypochlorite:
To determine the molar mass of KClO, sum the atomic masses of its constituent elements:
- Potassium (K): 39.10 g/mol
- Chlorine (Cl): 35.45 g/mol
- Oxygen (O): 16.00 g/mol
Calculating the total molar mass:
39.10 g/mol + 35.45 g/mol + 16.00 g/mol = 90.55 g/mol
Therefore, the molar mass of potassium hypochlorite is 90.55 g/mol. citeturn0search0
c. Number of Moles in 78.54 Grams of Potassium Hypochlorite:
To find the number of moles in a given mass, use the formula:
Number of moles = Mass (g) / Molar mass (g/mol)
Substituting the given values:
Number of moles = 78.54 g / 90.55 g/mol ≈ 0.867 moles
d. Total Number of Oxygen Atoms in 78.54 Grams of Potassium Hypochlorite:
First, determine the number of molecules in 0.867 moles using Avogadro’s number (6.022 × 10²³ molecules/mol):
Number of molecules = 0.867 moles × 6.022 × 10²³ molecules/mol ≈ 5.22 × 10²³ molecules
Since each molecule of KClO contains one oxygen atom, the total number of oxygen atoms is also approximately 5.22 × 10²³.
Explanation:
Potassium hypochlorite (KClO) is a compound formed by the combination of potassium ions (K⁺) and hypochlorite ions (ClO⁻). The molar mass of a compound is calculated by summing the atomic masses of all atoms present in its formula. For KClO, this involves adding the atomic masses of potassium, chlorine, and oxygen, resulting in a molar mass of 90.55 g/mol.
To determine the number of moles in a specific mass of a substance, divide the mass by the molar mass. In this case, 78.54 grams of KClO corresponds to approximately 0.867 moles. Avogadro’s number allows us to convert moles to molecules, indicating that 0.867 moles contain about 5.22 × 10²³ molecules. Since each molecule of KClO contains one oxygen atom, the total number of oxygen atoms in 78.54 grams is also approximately 5.22 × 10²³.
Understanding these calculations is essential in chemistry, as they enable precise quantification of substances involved in reactions, facilitating accurate predictions of reaction yields and the stoichiometry of chemical processes.