Question

Each year, the Department of Water Works measures the chloride concentration level in the water. The first year, they found the chloride concentration changed by −1 3/5 mg/L . It is estimated that the chloride concentration will change −2 1/15 mg/L the next year.

What is the total change that will likely occur in 2 years?

Answer 1

The concentration of chlorine in the solution, after calculating the moles from CaCl₂ and MgCl₂ and converting to grams, is found to be approximately 18.49 g/L.

Step-by-step explanation:

To calculate the concentration of chlorine in the solution, first, we need to know the amount of chlorine in the compounds given. The molecular weight of CaCl₂ is approximately 111 g/mol and that of MgCl₂ is about 95 g/mol. Each molecule of CaCl₂ contains two atoms of chlorine while each molecule of MgCl₂ also contains two atoms of chlorine.

Calculating the moles of chlorine from each compound:

For CaCl₂: (2 g / 111 g/mol) × 2 = 0.0360 mol of Cl

For MgCl₂: (2 g / 95 g/mol) × 2 = 0.0421 mol of Cl

Sum of moles of Cl = 0.0360 + 0.0421 = 0.0781 mol

Since 1 mole of Cl weighs about 35.5 g, the total mass of chlorine in the solution is 0.0781 mol × 35.5 g/mol = 2.7736 g.

To find the concentration in grams per liter (g/L), we convert the solution volume from 150 mL to 0.150 L:

Concentration of Cl = Total mass of Cl / Volume of solution in L

Concentration of Cl = 2.7736 g / 0.150 L = 18.491 g/L

Therefore, the concentration of chlorine in the solution is approximately 18.49 g/L.

Answer 2

-3 2/3 total change occurrence.