Final answer:
Use the formula Moles = Mass / Molar Mass to calculate moles of calcium chloride from its mass. The molar mass of CaCl₂ is 110.98 g/mol, and by dividing the mass of the sample by this molar mass, you can find the number of moles.
Step-by-step explanation:
To calculate the number of moles of calcium chloride given its mass, you should use the formula: Moles = Mass / Molar Mass. This allows you to convert a known mass of calcium chloride into moles, which is a fundamental concept in stoichiometry and chemical calculations.
First, find the molar mass of calcium chloride (CaCl₂), which is the sum of the atomic masses of calcium (Ca) and chlorine (Cl) multiplied by the number of atoms of each in the compound. The molar mass for CaCl₂ is 40.08 g/mol (for calcium) + 2 × 35.45 g/mol (for chlorine) = 110.98 g/mol. The number of moles is then calculated by dividing the mass of the CaCl₂ sample by its molar mass.
For example, if you have a sample with a mass of 3.00 moles of CaCl₂, then you would use the conversion factor that 1 mol equals 110.98 g to calculate the mass of CaCl₂ as follows:
- Multiply the number of moles (3.00 moles) by the molar mass of CaCl₂ (110.98 g/mol).
- The resulting mass is the product of these two values.
Therefore, 3.00 moles of CaCl₂ would have a mass of 3.00 moles × 110.98 g/mol = 332.94 g.