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Chem2 Unit 3: Acids and Bases (11 days)

Essential Questions

What are acids and bases?
Why kinds of chemical reactions occur with acids and bases?

Vocabulary

·      acid – a substance with a pH value less than 7 (from 0 to 6); these substances are tart/sour, feel sticky, react with metals to form hydrogen gas, and can be hazardous if strong

·      base – a substance with a pH value greater than 7 (from 8 to 14); these substances are bitter, feel slippery/slimy, and can be hazardous if strong

·      neutral – a substance with a pH of 7

·      (Review) electrical conductivity – a property of a substance that states how well it conducts electricity

·      dissociation reaction – a chemical equation showing what happens to a substance when it is placed in water; it is used to determine whether something is an acid or base

·      hydronium ion (H3O+) – an ion produced when a hydrogen ion (H+) combines with water (H2O)

·      hydroxide ion (OH-) – an ion produced when water loses a proton (H+ ion)

·      Arrhenius acid – a chemical that produces hydrogen ions (H+) [which then immediately form hydronium ions (H3O+)] in aqueous solutions

·      Arrhenius base – a chemical that produces hydroxide ions (OH-) in aqueous solutions

·      (NOT for mastery) Bronsted-Lowry acid – a chemical that donates protons (H+)

·      (NOT for mastery) Bronsted-Lowry base – a chemical that accepts protons

·      strong acid/base – a chemical that ionizes (dissociates) completely in a solvent; their dissociation reactions use a à symbol

·      weak acid/base – a chemical that only partially ionizes (dissociates) in a solvent; their dissociation reactions use a ó symbol

·      conjugate acid – the acid that forms when a base gains a proton (H+)

·      conjugate base – the base that forms when an acid loses a proton (H+)

·      (NOT for mastery) amphoteric – a substance that can act as either an acid or base under different conditions

·      [H3O+] – concentration of hydronium ions

·      [OH-] – concentration of hydroxide ions

·      pH – a value used to express how acidic or basic a substance is; it is a logarithmic representation of the hydronium ion concentration [H3O+]; pH values less than 7 are acidic and greater than 7 are basic

·      pOH – a value used to express how acidic or basic a substance is; it is a logarithmic representation of the hydroxide ion concentration [OH-]; pOH values less than 7 are basic and greater than 7 are acidic

·      (NOT for mastery) indicator – a compound that can reversibly change color depending on the pH of the solution; a common indicator is phenolphthalein

·      (Review) molar/formula mass – the mass of one mole of a compound with a given chemical formula; it is used to convert between grams and moles

·      neutralization reaction – the reaction of acids and bases to form water molecules and a salt

·      salt – an ionic compound containing a positive ion and a negative ion

·      equivalent point – the point at which the two solutions used in titration (an acid and a base) are present in equal amount; i.e. the point where the amount of hydronium ions equals the amount of hydroxide ions

·      titration – a method to determine the concentration of a substance in solutions by adding a solution of known volume and concentration until the reaction is completed, which is usually indicated by a change in color of an indicator

·      (NOT for mastery) end point – the point in a titration at which a marked color change takes place

·      acid ionization constant (Ka) – the equilibrium constant for a reaction in which an acid donates a proton to water (i.e. forms a hydronium ion); this constant relates to the strength of an acid



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  Jun 27, 2012, 9:28 AM Emilie Siverling
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