What is the mass percentage of iodine (i2) in a solution containing 4.0×10−2 mol i2 in 130 g of ccl4? express your answer using two significant figures. % request answer part b seawater contains 8.2×10−3 g sr2+ per kilogram of water. what is the concentration of sr2+ measured in ppm? express your answer using two significant figures. ppm p p m request answer

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)

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

Part B

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

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

Finally we calculate the concentration of Sr⁺²: