M

solutions, acids, and bases test review

vocabulary

  • soluble - capable of being dissolved

  • solute - substance that is dissolved (usually lesser amount)

  • solvent - substance that dissolves the solute (usually greater amount)

  • solution - homogeneous mixture of two or more substances in a single phase

    • .01-1nm
    • particles don’t settle
    • doesn’t separate with filtration
    • doesn’t scatter light

  • solubility - the amount of a substance of a solute required to form a saturated solution with a specific amount of solvent at a specified temperature

    • g solute/100g solvent
    • saturation point - the stage at which no more of a substance can be dissolved into a solution

  • electrolyte - substance that dissolves in water to give a solution that conducts electric current

  • non electrolyte - substance that dissolves in water to give a solution that does not conduct electric current

  • saturated solution - contains the maximum amount of dissolved solute

  • unsaturated solution - contains less solute than a saturated solution under the same conditions

  • supersaturated solution - contains more dissolved solute than a saturated solution contains under the same conditions

  • concentrated solution - contains a relatively high amount of dissolved solute

  • diluted concentration - contains a relatively low amount of dissolved solute

    • M1V1=M2V2

  • aqueous - dissolved in water

  • molarity(M) - (moles solute)/(liters solution)

  • suspension - heterogeneous mixture in which the particles are so large that they settle out unless the mixture is constantly agitated

    • particles settle out
    • 1000nm
    • separates with filtration
    • may scatter light but not transparent
    • ex oil in water, juice with pulp

  • colloid - heterogeneous mixture in which the particles are intermediate in size

    • 1-1000nm
    • particles don’t settle
    • particles don’t separate with filtration
    • scatter light -- Tyndall Effect: occurs when light is scattered by colloidal particles
    • ex jello, fog, milk

  • miscible - two liquids are miscible if they dissolve in each other in all proportions

  • immiscible - liquids are not soluble in each other

  • effervescence - rapid escape of a gas from a liquid in which it is dissolved (soda)

factors that affect solubility

⋆⋆composition is the only factor that determines whether or not something dissolves⋆⋆

↳ like dissolves like - polar solute will dissolve polar+ionic solutes, etc for nonpolar

  • temperature changes
    • solids+liquids - ↑temp=↑solubility
    • gases - ↑temp=↓solubility
  • pressure - only affects gas - ↑pressure=↑solubility
    • Henry’s Law - the solubility of a gas in a liquid is directly proportional to the partial pressure of that gas on the surface of the liquid
    • s1/p1=s2/p2

factors that affect rate of dissolution

  • temperature
  • surface area
  • agitation - shaking, stirring

ways to express “strength”/concentration

  • molarity M
  • % by volume = (volume solute)/(volume solution) x100
  • % by mass = (mass solute)/(mass solution) x100

properties of acids

  • produce H+ ions in water (hydronium ion)
  • taste sour
  • corrodes metal
  • weak/strong electrolytes
  • react with bases to form salt and water
  • pH less than 7
  • turns blue litmus to red
  • some acids react with active metals and release hydrogen gas H2
  • nomenclature review
    • -ide → hydro-ic acid
    • -ite → -ous acid
    • -ate → -ic acid

properties of bases

  • produce OH- ions in water
  • taste bitter, chalky
  • electrolytes
  • feel soapy, slippery
  • react with acids to form salt and water
  • pH greater than 7
  • turns red litmus blue

Arrhenius Acids and Bases

  • Arrhenius Acid - a chemical compound that increases the concentration of hydrogen ions H+ in an aqueous solution
    • molecular compounds with ionizable hydrogen atoms
    • strong acid ionizes completely in aqueous solution
    • weak acid releases a few hydrogen ions in aqueous solution
  • Arrhenius Base - a substance that increases the concentration of hydroxide ions OH- in an aqueous solution
    • most bases are ionic compounds that contain metal cations and the hydroxide anion OH-

Bronsted-Lowry Acids and Bases

  • Bronsted-Lowry Acid is a proton donor

    • monoprotic - can only donate one hydrogen ion, ex HNO3
    • polyprotic - can donate more than one hydrogen ion (one at a time) ex H2S

  • Bronsted-Lowry Base is a proton acceptor

  • the stronger an acid is, the weaker its conjugate base

  • the stronger a base is, the weaker its conjugate acid

Self Ionization of Water

  • in water at 25°C
    • [H3O+]=1.0x10^-7M
    • [OH-]=1.0x10^-7M
    • ionization constant of water: [H3O+][OH-]=1x10^-14

pH

  • defined as the negative of the common logarithm of the hydronium ion concentration

    • pH = -log[H+]
    • pOH = -log[OH-]
    • pH+pOH = 14
    • [H+]M = 10^(-pH)
    • [OH-]M = 10^(-pOH)

  • neutralization occurs when hydronium ions and hydroxide ions are supplied in equal numbers by reactants [H+]=[OH-]

  • titration - the controlled addition and measurement of the amount of known concentration required to react completely with a measured amount of a solution of unknown concentration

    • equivalence point - point at which the two solutions used in a titration are present in chemically equivalent amounts
    • end point of indicator - point at which an indicator changes color
    • standard solution - contains the precisely known concentration of a solute
    • primary standard - highly purified solid compound used to check the concentration of the know solution in a compound
    1. start with a balanced chemical equation
    2. determine moles of acid or base from the known solution used in the titration
    3. determine moles of solute of the unknown solution used during the titration
    4. determine molarity of unknown solution