Question

How many molecules of CaCl2 are equivalent to 75.9g CaCl2 (Ca=40.08g/mol, CL=35.45g/mol)

Answer 1

`\large \boxed{4.12 * 10^(23)\text{ formula unis of CaCl}_(2)}$}`

Step-by-step explanation:

You must calculate the moles of CaCl₂, then convert to formula units of CaCl₂.

1. Molar mass of CaCl₂

CaCl₂ = 40.08 + 2×35.45 = 40.08 + 70.90 = 110.98 g/mol

2. Moles of CaCl₂
`\text{Moles of CaCl}_(2) = \text{75.9 g CaCl}_(2) * \frac{\text{1 mol CaCl}_(2)}{\text{110.98 g CaCl}_(2)} = \text{0.6839 mol CaCl}_(2)`

3. Formula units of CaCl₂

`\text{No. of formula units} = \text{0.6839 mol CaCl}_(2) * \frac{6.022 * 10^(23)\text{ molecules CaCl}_(2)}{\text{1 mol P$_(2)$O}_(5)}\\\\= \mathbf{4.12 * 10^(23)}\textbf{ formula units CaCl}_(2)\\\text{There are $\large \boxed{\mathbf{4.12 * 10^(23)}\textbf{ formula units of CaCl}_(2)}$}`