Question

2. "Like Dissolves Like: Polarity and Solubility A. Polar Solvent: Water Salute Iodine Sodium chloride Obseruation Chip didn't dissolve some solid on Bottom Solid completely dissolved Chip floated on top of water Floated on top of water Sugar Wax Cooking oil of these solute? 1. What patterns do you observe regarding the polar and non-polar characteristics of these se 2. What effect do you think heating would have on the solubilities of these substances? B. Non-Polar Solvent: Toluene Solute lodine Sodium chloride Sugar Observations solution turned purple No solid dissolued. No solid dissolved Chip completely dissolved Mix tune tureed yellow Wax Cooking oil

Answer 1

1) When the electronegativity difference between the two atoms in a bond are high and the most electronegative atom attracts the shared pair of electrons towards it. This leads to the development of a partial charge seperation within the molecule. The more electronegative atom attains a partial negative charge and the less electronegative atom attains a partial negative charge. Then the molecule is said to be polar.

Iodine, wax, cooking oil are non-polar. They are insoluble in polar solvents like water. They are soluble in non-polar solvents like toluene only. A polar molecule has partial positive and negative charge in it. When come in contact with a polar solvent like water, the opposite charges attract and this make them soluble in water.

2) Heating has little effect on the solubility of these substances.

Heating has little effect in the solubility of NaCl it can be clearly observed from the solubility curve of NaCl.

Sugar is already soluble in water and has nothing to do with heating

Iodine, wax, cooking oil will not dissolve in water even after heating. They can be dissolved in non-polar solvents only. Their solubilities in non-polar solvents may increase upon heating depending upon the solvent. When a non-polar solvent is partially miscible in a non-polar solvent, the solubility can be increased by heating.