Water: The Universal Solvent
- Water is a very versatile solvent because polar molecules are attracted to other polar molecules + its molecules form HB (adhesive)
○ (+) and (-) attraction
- Why are ionic compounds soluble in water?
○ When ionic compounds are dissolved, the dipole of the water interacts with the charged ions and causes them to separate
○ The strong ionic bonds between the positive and negative ions of the solid are replaced by stronger ion-dipole interactions between the ions & water → the interaction is energetically favorable
- Hydration: “positive ends” of the water molecules are attracted to the negatively charged anions and that the “negative ends” are attracted to the positively charged cations
- When ionic substances (salts) dissolve in water, they break up into the individual cations and anions.
The Nature of Aqueous Solutions: Strong and Weak Electrolytes
- Electrical conductivity: its ability to conduct an electric current
- Electrolyte: compound that conducts an electric current when dissolved in water or melted
○ Has charged particles
Strong Electrolytes
- Strong electrolytes: substances that completely ionizes when they are dissolved in water (Ex: NaCl)
○ All ionic compounds and strong acids/bases are strong electrolytes
- Aqueous solutions with them conduct an electric current very efficiently
Weak Electrolytes
- Weak electrolytes: only a few ions produced when dissolved in water (ex: acetic acid)
○ Solutions with them conduct only a small current
○ Weak acid (NH4+ ammonium ion)/base (NH3 ammonia) = weak electrolyte
Nonelectrolytes
- Nonelectrolyte: substances that dissolves in water but do not produce any ions (ex: sugar, ethanol) → instead entire molecules dispersed in the water → solution does not conduct an electric current