Solutions of Electrolytes Students will identify electrolytes and explain why they are more affective in lowering the freezing points than non-electrolytes

C12H22O11 and C2H6O2

What is an Electrolyte? Pure water does not conduct electricity An electrolyte is substance that when dissolved in water the resulting solution conducts electricity. They do this by breaking into ions.

Weak Electrolytes When these compounds are added to water they do not ionize (breakup) completely

Non-electrolytes Are compounds such as sugar and ethylene glycol that do not ionize in water. Since they do not breakup into ions they do nothing to help water carry a charge.

Strong Electrolytes Breakup Completely.

Colligative Properties Are properties that depend only on the # of dissolved particles not on the type of particle. The two properties we are concerned about are boiling and freezing points.

Electrolytes almost always contain a metal in the formula Which are electrolytes? NaCl C12H22O11 C2H5OH KNO3 LiF

Ionic compounds and molecular Compounds For every molecule of compounds like antifreeze and sugar you add to water, you get one solute particle. But for every NaCl unit added to water, you get two solute particles because they break into positive and negative ions.

Adding non electrolytes to water

The “i” factor The “i” factor is the number of particles the unit becomes when it dissolved in water. For non-electrolytes the value is one. For strong electrolytes, it is the number of ions that make up the compound. For example, Ba(NO3)2 has one barium ion and two nitrate ions. The “i” factor is 3

25 grams NaCl in 100 grams of water Sodium Chloride is an electrolyte NaCl  Na+ + Cl- 1.00 mole NaCl = 58.5 grams Moles NaCl = 25/58.5 = 0.427 Moles of particles = 2 x 0.427 = 0.855