What is the molar mass of lead (II) iodide? 334 g 461 g 668.2 g
The correct answer and explanation is:
The correct answer is 461 g.
To calculate the molar mass of lead (II) iodide (PbI₂), follow these steps:
- Identify the atomic masses: The atomic mass of lead (Pb) is approximately 207.2 g/mol, and the atomic mass of iodine (I) is about 126.9 g/mol.
- Determine the number of atoms in the formula: In PbI₂, there is one lead atom and two iodine atoms.
- Calculate the total mass:
- The contribution of lead (Pb) is 1 × 207.2 g/mol = 207.2 g/mol.
- The contribution of iodine (I) is 2 × 126.9 g/mol = 253.8 g/mol.
- Add the individual contributions: The total molar mass is: 207.2 g/mol+253.8 g/mol=461 g/mol.207.2 \, \text{g/mol} + 253.8 \, \text{g/mol} = 461 \, \text{g/mol}.
Thus, the molar mass of lead (II) iodide is 461 g/mol.
Understanding molar mass is important because it allows for conversions between the mass of a substance and the number of moles. A mole is defined as 6.022 × 10²³ particles, and the molar mass represents the mass of one mole of a substance. The molar mass is often used in stoichiometry to calculate how much of each reactant or product is involved in a chemical reaction.
In this case, knowing the molar mass of PbI₂ is useful for determining how much lead (II) iodide is needed to prepare a certain number of moles or for calculating the mass of the compound produced in a reaction.