Acids, Bases, and Solutions

Chapter 7

What is a Solution?

SolutionsSame properties throughoutContains a solvent and a solute

SolventDoes the Dissolving

Water = Liquid

SoluteThe stuff that is dissolved

Sugar

Kool-Aid

Solvent = Water

Solute = Sugar

Water is referred to as the “universal Solvent”

Why?

Water dissolves almost anything

ConcentrationHow much solute (dissolved stuff)

DiluteWeakNot a lot of solute (dissolved stuff)

ConcentratedStrongA lot of solute (dissolved stuff)

Measuring Concentration

Amount of SoluteAmount of Solvent

X 100

ExampleA solution contains 12 g of solute dissolved in 36 g of solution. What is its concentration?

Answer: 10%

12 g36 g = .33 x 100

.33 = 33%

ExampleWhat is the concentration of a solutions that contains 45 grams of sugar in 500 grams of solution?

Answer: 9%

45 g500 g= .09 x 100

.09 = 9%

ExampleHow much sugar is dissolved in 500 grams of a solution if the solution is 70 percent sugar by mass?

Answer: 350gX500 g 70%=

.7 (500) = x

X = 350g

SolubilityA measure of how much solute (dissolved stuff) can dissolve

Unsaturated Solution

Weak, DiluteVery little solute is added

Add more sugar it will dissolve

Saturated Solution

Perfect AmountNo more solute will dissolve

If you add more it will settle to the bottom

SupersaturatedAdd so much solute that it begins to pile up on the bottom of the container

Acids and Bases

IndicatorsCompounds that change color when it contacts an acid or a base

Properties of AcidsSour tasteReacts with metals (corrosive)

Turns litmus paper red

Properties of BasesBitter TasteSlippery FeelTurns Litmus paper Blue

AcidsProduce Hydrogen Ions (H+) in water

BasesProduce Hydroxide ions (OH-) ions in water

Strengths of Acids and Bases

The pH scale

The pH scaleRange of numbers from 1-14

Ph < 7ACIDIC H+ ions presentThe lower the number the stronger the acid (more H+ ions)

pH = 7NeutralNot acidic or basic H+ = OH- ions

pH > 7BASIC OH- ions presentThe higher the number the more basic

NeutralizationA reaction between an acid and a base

Salt and water produced

Neutralization

Check for Understanding

pH 1, pH 3 or pH 7 ?

Which contains the highest concentration of Hydrogen ions?

pH of 1

pH of 6 or pH of 3

Which is stronger?Which contains more H+ ions?

pH of 3

pH 10 or pH 14Which is a stronger base?

Which has more OH- ions?

pH of 14