Acids, Bases, & Solutions

Solutions Solution-uniform mixture that contains a solvent & solute Solution-uniform mixture that contains a solvent & solute Solvent-the part of the solution that is present in the largest amount Solvent-the part of the solution that is present in the largest amount Solute-the part of the solution that is present in the smaller amount and is dissolved…so is Mr. Inman’s brain hee hee. Solute-the part of the solution that is present in the smaller amount and is dissolved…so is Mr. Inman’s brain hee hee. Water is the universal solvent, but solvents and solutes may be solids, liquids, or gases Water is the universal solvent, but solvents and solutes may be solids, liquids, or gases Has the same properties throughout Has the same properties throughout

Colloids a mixture that contains small undissolved particles, particles are too small to be seen, but large enough to scatter light a mixture that contains small undissolved particles, particles are too small to be seen, but large enough to scatter light

Suspension Does not have the same properties though out Does not have the same properties though out Contains visible particles Contains visible particles Mrs. Dunham likes little dogs Mrs. Dunham likes little dogs

Effects of Solute & Solvents Solutes lower the freezing point & raise the boiling point of a solvent Solutes lower the freezing point & raise the boiling point of a solvent Mr. C. is really hot. Mr. C. is really hot.

Concentration Concentrated solution-lots of solute, little solvent Concentrated solution-lots of solute, little solvent Ex. Frozen juice Ex. Frozen juice Dilute solution-little solute, lots of solvent Dilute solution-little solute, lots of solvent Ex. Frozen juice + water Ex. Frozen juice + water Measuring concentration- compare amount of solute to solvent Measuring concentration- compare amount of solute to solvent Ex. 5 grams per 100mL Ex. 5 grams per 100mL

Solubility How much solute can dissolve in a solvent at a given temperature How much solute can dissolve in a solvent at a given temperature Unsaturated-can hold more solute Unsaturated-can hold more solute Saturated-can NOT hold more solute Saturated-can NOT hold more solute Supersaturated-too much solute, some is undissolved at the bottom of the container Supersaturated-too much solute, some is undissolved at the bottom of the container

Factors affecting solubility Pressure Pressure Increasing the pressure increases the solubility and vise- versa Increasing the pressure increases the solubility and vise- versa Type of solvent Type of solvent Some solutes & solvents are incompatable Some solutes & solvents are incompatable Ex. Oil and vinegar Ex. Oil and vinegar The solvent affects the solubility of a substance The solvent affects the solubility of a substance Ex. Oil-based paint & water Ex. Oil-based paint & water

Temperature Temperature Solids-increasing the temp. increases solubility Solids-increasing the temp. increases solubility Gases- increasing temperature decreases solubility Gases- increasing temperature decreases solubility

Acids and Bases Chemicals may be classified as acids or bases. Chemicals may be classified as acids or bases. Things that are neither acids nor bases are neutral. Things that are neither acids nor bases are neutral. pH measures how acidic or basic a solution is. pH measures how acidic or basic a solution is.

Acids Taste sour Taste sour Turns blue litmus paper red Turns blue litmus paper red Reacts with metals/carbonates Reacts with metals/carbonates Contains hydrogen ions H + Contains hydrogen ions H + Examples: Examples: Lemon juice Lemon juice Vinegar Vinegar Car battery acid Car battery acid (dangerous!)

Some of our favorite foods make our tongue curl up because they are SOUR. Some of our favorite foods make our tongue curl up because they are SOUR. Acids and Bases

Bases Taste bitter Taste bitter Slippery feel Slippery feel Turns red litmus paper blue Turns red litmus paper blue Contains hydroxide ions OH - Contains hydroxide ions OH - Turns Phenolphthalein pink Turns Phenolphthalein pink Examples: Examples: Milk Milk Baking soda Baking soda Soap Soap Drain cleaner Drain cleaner (dangerous!)

Bitter! Some foods have a “bite” of their own because they’re somewhat bitter. Some foods have a “bite” of their own because they’re somewhat bitter.

pH A special name is given to the acid or base characteristic that a substance has: A special name is given to the acid or base characteristic that a substance has: It is called: pH It is called: pH

How Do We Measure pH? We measure pH by using special strips of paper called pH paper We measure pH by using special strips of paper called pH paper

How Does It Work? The paper is treated with chemicals that change color to show the pH. The paper is treated with chemicals that change color to show the pH. When the paper touches the substance being tested, it turns a specific color to tell if the substance is an acid or a base. When the paper touches the substance being tested, it turns a specific color to tell if the substance is an acid or a base.

The pH Scale pH scale ranges from pH scale ranges from pH 7 is neutral; neither acid nor base pH 7 is neutral; neither acid nor base Pure water is pH 7 Pure water is pH 7 Low pH = acid Low pH = acid High pH = base High pH = base The closer to the ends of the scale, the stronger the solution is The closer to the ends of the scale, the stronger the solution is

Acid Any substance which has a pH of value of less than 7 is considered an acid Any substance which has a pH of value of less than 7 is considered an acid Acid Neutral Base Acid Neutral Base

Base Any substance which has pH value greater than 7 is a base Any substance which has pH value greater than 7 is a base Acid Neutral Base Acid Neutral Base

pH 7 A pH of 7 is called neutral—neither acid nor base. A pH of 7 is called neutral—neither acid nor base Acid Neutral Base

The pH Scale

Each pH unit is 10 times as large as the previous one Each pH unit is 10 times as large as the previous one A change of 2 pH units means 100 times more basic or acidic A change of 2 pH units means 100 times more basic or acidic Each pH unit is 10 times as large as the previous one Each pH unit is 10 times as large as the previous one A change of 2 pH units means 100 times more basic or acidic A change of 2 pH units means 100 times more basic or acidic x10x100

Acid-Base Reactions Neutralization-a reaction in which an acid reacts with a base to produce salt and water Neutralization-a reaction in which an acid reacts with a base to produce salt and water HCl + NaOH= H 2 O + NaCl HCl + NaOH= H 2 O + NaCl