Chapter 6 Solutions, Acids, and Bases

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Chapter 6 Solutions, Acids, and Bases
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Physical ScienceChapter 6 Section 1

• Objectives
• Distinguish between homogeneous mixtures and
  heterogeneous mixtures.
• Compare and contrast the properties of solutions,
  colloids, and suspensions.
• Identify ways to separate different kinds of
  mixtures.

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Mixtures

• Heterogeneous
• Homogeneous

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Heterogeneous Mixtures

• Different throughout
• Includes suspensions and colloids
• Can be immiscible
• Two liquids will not mix
• ex. oil and water

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Suspensions

• Mixture that looks uniform when stirred and
  separates into different layers when still
• Particles are 1000 nm or larger
• ex. blood
• Can be separated by densities of liquids, by
  difference in boiling points, or by
  chromatography

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Demo.

• Chromatography
• Separation of dyes in an ink

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Colloids

• Mixture of very tiny particles dispersed in
  another substance, but do not settle out
• Particles are 1 100 nm
• ex. egg white, paint, whipped cream, marshmallow,
  smoke, fog

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Emulsion

• Mixture of immiscible liquids in which the
  liquids are spread throughout one another
• Prevent separation
• Appear uniform
• Can be colloids
• ex. egg yolk in mayonnaise

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Demo.

• Solution or not
• Jello water vs. sugar water
• What are your observation?
• Which substance has the larger particles?
• jello
• Did anything settle out?
• No
• How would you classify the sugar water?
• Solution
• How would you classify the jello water?
• colloid

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Demo.

• Emulsion
• Making butter
• The emulsion here is the cream
• Lipids stuck together and water is the liquid
  remaining

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Homogeneous Mixtures

• Uniform throughout
• Are solutions
• ex. salt water, sugar water, lemonade

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Solutions

• Homogeneous mixture of 2 or more substances
  uniformly spread in a single phase
• Consists of a solute and solvent
• Miscible liquids

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Review and Assignment

• Distinguish between homogeneous mixtures and
  heterogeneous mixtures.
• Compare and contrast the properties of solutions,
  colloids, and suspensions.
• Identify ways to separate different kinds of
  mixtures.
• Assignment page 191 1-6 and WS

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Physical ScienceChapter 6 Section 2

• Objectives
• Identify several factors that affect the rate at
  which a substance dissolves.
• Relate the structure of water to its ability to
  dissolve many different substances.
• Distinguish between saturated, unsaturated, and
  supersaturated solutions.

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Solute and solvent

• Solvent substance that dissolves the solute
• Can be solid in liquid, liquid in liquid, gas in
  liquid, solid in solid, and gas in gas
• Solute substance that dissolves

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Solubility

• Greatest quantity of solute that will dissolve to
  produce a saturated solution
• Affected by 3 factors
• Not every substance dissolves
• Can be insoluble or partially soluble

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1. Surface Area

• Solutes w/larger surface areas dissolve faster
• Smaller pieces dissolve faster

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2. Stirring/shaking

• Increases the contact between particles
• Allows more particles to interact

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3. Temperature

• Increasing temperature, increases dissolving
• Particles move faster so more particles collide

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Water as a solvent

• A universal solvent
• b/c so many things dissolve in it
• Water is polar
• Has a and end
• Other molecules w/charges are attracted to water
• To know if something will dissolve in water use
  like dissolves like rule
• Polar and polar
• Non-polar and non-polar

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Demo.

• Which is more polar water or ethanol?
• Iodine is non-polar

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Concentration

• Quantity of solute dissolved in a given amount of
  solution

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Dilute

• Small amount of solute dissolved in a large
  amount of solvent

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Concentrated

• Large amount of solute dissolved in a solvent

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Unsaturated

• Solution that is able to dissolve more solute

solubility (36g for NaCl).
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Saturated

• Solution that cannot dissolve any more solute at
  a given temperature and pressure
• Is in equilibrium

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Supersaturated

• Increase in temperature leads to increased
  solubility
• Solution holding more dissolved solute than is
  normal at a given temperature
• Very unstable

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Demo.

• Temperature and solubility
• What did you see before heating the solution?
• What did you see after heating the solution?
• What happened?

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Measuring concentration precisely

• Use molarity
• Molarity (M) moles of solute
• L of solution

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Review and Assignment

• Describe how a substance dissolves in terms of
  its solubility, molecular motion, and
  solute-solvent interactions.
• Identify several factors that affect the rate at
  which a substance dissolves.
• Relate the structure of water to its ability to
  dissolve many different substances.
• Distinguish between saturate, unsaturated, and
  supersaturated solutions.
• Assignment WS

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Physical ScienceChapter 6 Section 3

• Objectives
• Compare and contrast acids and bases.
• Relate the pH of a solution to the concentration
  and strength of dissolved acid or base.
• Identify the products of neutralization reactions.

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Acids

• Substances that donate H to form H3O when
  dissolved in water
• Taste sour
• Turn blue lithmus red
• ex. lemon and limes (citric acid)
• Vinegar (acetic acid)
• Can conduct electricity when dissolved in water

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Strong Acids

• Fully ionize
• Have as many H3O as they can
• ex. HCl, H2SO4, HNO3

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Weak Acids

• Do not fully ionize
• Do not conduct electricity as well as strong
  acids
• ex. C2H3O2, H2CO2, HF

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Bases

• Substance that either contains OH- ions or reacts
  w/water to form OH- ions
• Taste bitter
• Feel slippery
• Can conduct electricity
• Turn red lithmus blue
• Can be dangerous
• ex. drain cleaners, baking soda, antacids

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Strong bases

• Contain OH-
• Conduct electricity well
• OH- dissociates completely

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Weak bases

• React with water to form OH-
• Poor conductors

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pH

• Stands for pouvoir hydrogene (french)
• Measures concentration of hydronium (H3O) ions
• Also indicates OH- concentrations
• Tells us if something is neutral, acidic, or
  basic
• Ranges from 0 to 14

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pH

• 7 is neutral
• ex. pure water
• H3O and OH- are equal
• Less than 7
• Acidic
• ex. apple juice
• H3O greater than OH-
• More than 7
• Basic
• ex. ammonia
• OH- greater than H3O

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Inquiry lab

• p. 204

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Neutralization

• Reaction of an acid w/a base to form water and a
  salt
• H3O from acid and OH- from base forms water
• HCl H2O ? H3O Cl-
• NaOH ? Na OH-
• Not all rx. btwn acids and bases end up neutral
• pH d/o whether the acids and bases are strong or
  weak
• Chart p. 204

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Review and Assignment

• Compare and contrast acids and bases.
• Relate the pH of a solution to the concentration
  and strength of dissolved acid or base.
• Identify the products of neutralization
  reactions.
• Assignment WS

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Physical ScienceChapter 6 Section 4

• Objectives
• Recognize several acidic and basic substances
  commonly found in homes.
• Explain how soap is made and why it can remove
  dirt and grease.
• Describe the acidic or basic characteristics of
  other household items.

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Acids and bases in the home

• Soap
• Detergent
• Shampoo
• Antacid
• Vitamins
• Juices
• Cleaning products

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Soaps

• Dissolve grease and oil in water
• Are emulsifiers that allow oil and water to mix
• This is why soap is a good cleaner
• Soap is made from lard or oil and NaOH (lye) or
  KOH
• Have a and end
• This is what is attracted to the water
• Make soap

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Detergents

• Charged end is SO3-
• Formed from petroleum products
• This allows them to clean better
• Detergent and water

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Ammonia Solutions

• Good cleaners
• NH3 and water
• Emulsifies grease and dirt
• The OH- formed interacts w/grease and dirt and
  forms an emulsion w/water

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Disinfectants

• Substance that kills harmful bacteria and viruses
• Bleach (NaClO2) or (NaOCl)
• Basic b/c is feels slippery
• Oxidizes stains

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Other household acids and bases

• Acidic dyes in clothing
• Antacids
• Weak base
• Neutralizes stomach acid
• Vitamin C is ascorbic acid
• Aspirin is actylsalicyclic acid

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Inquiry lab

• p. 210

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Shampoos

• Are detergents
• Remove oil and buildup from hair
• Usually pH between 5 and 8
• If shampoo is too basic hair, becomes dull
• Is shampoo is too acidic, hair becomes too dry

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Acids and Bases in the kitchen

• Fruits
• Lemon juice (citric acid)
• Vinegar used for marinating
• Baking soda - base

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Review and Assignment

• Recognize several acidic and basic substances
  commonly found in homes.
• Explain how soap is made and why it can remove
  dirt and grease.
• Describe the acidic or basic characteristics of
  other household items.
• Assignment WS