Outline the successive steps in the crystallization of an organic solid from a solvent and state the purpose of each operation. (1.5 points)

A. 7.2%

B. 8.6 ppm

Explanation:

Part A

First let's calculate the mass of I₂, using the known value of moles and the molecular weight (253.8 g/mol)

4.0x10⁻² mol I₂ * 253.8 g/mol = 10.152 g I₂

Mass percentage is calculated using the mass of I₂ and the total mass (mass of I₂ + mass of CCl₄)

Total mass = 130 + 10.152 = 140.152 gMass percentage I₂ = 10.152 / 140.152 * 100 = 7.2%

Part B

The concentration of Sr⁺² in ppm is calculated using the formula

mg Sr⁺² / L water

We're given the mass of Sr⁺² in grams, so now we convert it into mg:

8.2x10⁻³g * = 8.2 mg

Now to convert kg of water into L, we use the density of seawater (1050 kg/m³):

Converting density: 1050 *   = 1.05 kg/L

Volume of one kilogram of water = 1kgWater ÷ 1.05 kg/L = 0.95 L

Finally we calculate the concentration of Sr⁺²:

8.2 mg / 0.95 L = 8.6 ppm