Question

concept check

1. predict what would happen if you mixed potassium chloride (kcl) with water. optional: draw and label a diagram to justify your explanation.
2. identify one property of water that contributes to the suitability of the environment for marine life.
3. predict one disruption that would occur in the environment if ice was more dense than water.

Explanation:

Question 1

Step1: Recall KCl solubility

KCl is an ionic compound, water is polar. Ionic compounds dissolve in polar solvents via hydration.

Step2: Describe dissociation

When KCl mixes with water, \( \text{KCl}(s) \xrightarrow{\text{H}_2\text{O}} \text{K}^+(aq) + \text{Cl}^-(aq) \). Water molecules surround ions (hydration), so KCl dissolves, forming a homogeneous solution.

Water has high specific heat capacity, meaning it resists temperature changes. This stabilizes marine environments, providing a consistent thermal habitat for marine life. Alternatively, water's ability to dissolve many substances (universal solvent) allows nutrients and gases to be available for marine organisms. Or, water's density anomaly (ice less dense than liquid water) keeps oceans/lakes from freezing solid, preserving marine habitats.

Normally, ice floats (less dense than water), insulating the water below. If ice were more dense, it would sink. In cold conditions, ice would accumulate at the bottom of bodies of water (lakes, oceans). This would cause water bodies to freeze from the bottom up, destroying marine habitats (organisms would be trapped in freezing water, and the insulating layer would be lost). Ecosystems would collapse as temperatures drop throughout the water column, and seasonal freezing would permanently freeze many water bodies.

Answer:

Potassium chloride (KCl) will dissolve in water. The ionic bonds in KCl break, and \( \text{K}^+ \) and \( \text{Cl}^- \) ions become hydrated (surrounded by water molecules), resulting in a homogeneous aqueous solution.

Question 2