Name: Solutions Part II - Notes Electrolyte ● A substance that will conduct electricity through a solution, when dissolved in water. ● Solutions that contain an electrolyte are called electrolytic solutions. ● Ex ­ Salt Nonelectrolyte ● A substance that is also soluble in water, but when dissolved, does not conduct electricity. ● Ex ­ Sugar Electrolytic Dissociation ● The separation of a dissolved compound, (the solute), into two ions of opposite charges. ● Ex ­ NaCl₍
₎
→ Na⁺
₍
ₐ ₎
+ Cl⁻
₍
ₐ ₎ ● The subscripts in parentheses describe the state of each substance, s for solid and aq for aqueous. The H₂
O over the arrow indicates that this occurs when the solute is placed in water. The + and ­ are the charges that each Na and Cl take on when dissolved in water. Ion ● An atom that has becomes electrically charged by either gaining or losing electrons. ● Ions formed during electrolytic dissociation will conduct electricity in a solution. ● Ex ­ In the above equation, Na lost an electron to become positively charged, and Cl took on that electron to become negatively charged. ● When a nonelectrolyte is dissolved in water, no ions are formed. Acids ● A substance that releases H⁺
ions in a solution. ● Usually start with an H in their chemical formula, (exception is acetic acid, CH₃
COOH). ● Will turn blue litmus paper red and red litmus paper remains red. ● Have a pH less than 7. ● Conduct electricity. ● Ex ­ HCl, H₂
SO₄
, fruit juices, soft drinks, gastric juices. Bases ● A substance that releases OH⁻
ions in a solution. ● Usually ends with an OH in their chemical formula, (exception is ammonia, NH₄
). ● Will turn red litmus paper blue and blue litmus paper remains blue. ● Have a pH greater than 7. ● Conduct electricity. Name: ●
Ex ­ NaOH, NH₄
OH, cleaning products, blood, heartburn medication. Salts ● A substance produced by bonding a metal and a nonmetal, (other than H⁺
and OH⁻
). ● Litmus papers will not change, (blue stays blue, red stays red). ● pH is equal to 7. ● Conduct electricity when dissolved in water. ● Ex ­ NaCl, AgNO₃
pH Scale ● A scale ranging from 0 to 14 that classifies substances as being either acidic or basic. ● Works on a scale of ten, so: ○ pH 8 is ten times more basic than pH 7. ○ pH 2 is 1000 times more acidic than pH 5. ● Acids and bases can be neutralized by introducing the corresponding pH level on the other side of the scale. ○ To neutralize pH 5, introduce pH 9. ○ To neutralize pH 11, introduce pH 3. ● Distilled water: ○ pH of 7. ○ Will not change litmus paper. ○ Does NOT conduct electricity because there are no electrolytes.