Question

a student has a 5.00 gram sample of calcium chloride (CaCl2) solid. how many miles of calcium chloride are contained in this sample

Answer 1

0.0451 moles ≅ 0.04 moles

Step-by-step explanation:

We can calculate how many moles of calcium chloride (CaCl₂) are in 5.00 g sample, by dividing the mass into the molar mass (MM) of the compound:

moles = mass/MM

First, we calculate MM of CaCl₂ from the chemical formula, using the molar mass of the elements Ca and Cl:

MM CaCl₂ = (1 x MMCa) + (2 x MMCl) = 40 g/mol + ( 2 x 35.453 g/mol)

= 110.9 g/mol

Finally, we calculate the moles from the mass and MM:

moles of CaCl₂ = mass/(MM CaCl₂) = 5.00 g/(110.9 g/mol) = 0.0451 moles ≅ 0.04 moles