Chem UNIT 2: Acids, Bases and Salt Preparations

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Solubility Rules
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Terms in this set (61)
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Solubility Rules
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Specification Point 2.34:
Know the common rules for prediction the solubility of ionic compounds in water: Common Sodium, Potassium and Ammonium Compounds are soluble, all Nitrates are soluble, Common Chlorides are soluble except those of Silver and Lead (II), Common Sulfates are soluble, except for those of Barium, Calcium and Lead (II), Common Carbonates are insoluble, except for those of Sodium, Potassium and Ammonium, Common Hydroxides are insoluble except for those of Sodium, Potassium and Calcium (Calcium Hydroxide is slightly soluble)
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Neutralisation: Proton Transfer
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Solubility Rules

State the solubility rules
Image: ++++ Solubility Rules State the solubility rules
Specification Point 2.35:
Understand Acids and Bases in terms of Proton transfer
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Acids and Bases (Alkalis)
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Acids
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What happens when atoms or groups of atoms lose or gain electrons?
they form charged particles called ions.
What happens when acids react?
When acids react, they will lose electrons to form positive hydrogen ions (H+).
What makes aqueous solutions acidic?
H+ Ions
Example: Hydrochloric Acid What does Hydrochloric Acid look like when dissociated in aqueous form?HCl (aq) → H+ (aq) + Cl- (aq)+++ Bases (Alkalis):What happens when Alkalis react?they will gain electrons to form negative hydroxide ions ( OH- ).What makes an aqueous solution alkali?OH- IonsExample: Sodium Hydroxide What does NaOH look like dissociated in aqueous form?NaOH (aq) → Na+ (aq) + OH- (aq)***Summary Acids and Bases (Alkalis) ---When atoms, or groups of atoms, lose or gain electrons, they form charged particles called ions. ---These ions can be either positively or negatively charged. *Acids: When acids react, they will lose electrons to form positive hydrogen ions (H+). These H+ Ions makes the aqueous solution acidic. Example: Hydrochloric Acid HCl (aq) → H+ (aq) + Cl- (aq) *Bases (Alkalis): When Alkalis react, they will gain electrons to form negative hydroxide ions ( OH- ). These OH- Ions makes the aqueous solution an alkali. Example: Sodium Hydroxide NaOH (aq) → Na+ (aq) + OH- (aq)Specification Point 2.36: Understand that an Acid is a Proton Donor and a Base is a Proton Acceptor+++ Acids and Bases (Alkalis)*** Turn for pic The role of Acids and Bases in the transfer of ProtonsWhat are acids in terms of proton transfer?Acids are a proton donor as they will react to lose electrons to form positive H+ ionsWhat are bases/alkalis in terms of proton transfer?Bases (alkalis) are proton acceptors as they will react to gain electrons to form negative OH- ions*** Summary *Acids: Acids are a proton donor as they will react to lose electrons to form positive H+ ions These H+ ions makes the aqueous solution acidic *Bases (Alkalis): Bases (alkalis) are proton acceptors as they will react to gain electrons to form negative OH- ions These OH- ions makes the aqueous solution acidic+TOPIC+ Neutralisation: Acids, Bases, Metals, Carbonates & SaltsSpecification Point 2.37: Describe the reactions of Hydrochloric Acid, Sulfuric Acid and Nitric Acid with Metals, Bases and Metal Carbonates (Excluding the reactions between Nitric Acid and Metals) to form Salts+++ Reacting Acids with MetalsOnly metals above hydrogen in the reactivity series will react with dilute acids. Acids will react with metals to form a salt and hydrogen gas: Acid + Metal → Salt + Hydrogen *** Turn for pic Examples of Reaction Between Acids and Metals:*** Summary Reacting Acids with Metals Only metals above hydrogen in the reactivity series will react with dilute acids. Acids will react with metals to form a salt and hydrogen gas: Acid + Metal → Salt + Hydrogen+++ Reacting Acids with Bases (Alkalis)What types of compounds can act as bases?All metal oxides, metal hydroxides can act as bases.*** All metal oxides, metal hydroxides can act as bases. When they react with acid, a neutralisation reaction occurs. Acids and bases will react to produce a salt and water: Acid + Base → Salt + Water *** Turn for pic Examples of Reaction Between Acids and Bases:***Summary Reacting Acids with Bases (Alkalis) All metal oxides, metal hydroxides can act as bases. When they react with acid, a neutralisation reaction occurs. Acids and bases will react to produce a salt and water: Acid + Base → Salt + Water+++ Reacting Acids with Metal CarbonatesAcids will react with metal carbonates to form salts, carbon dioxide and water: Acid + Metal Carbonate → Salt + Carbon Dioxide + Water *** Turn for pic Examples of Reaction Between Acids and Bases:*** Summary Reacting Acids with Metal Carbonates Acids will react with metal carbonates to form salts, carbon dioxide and water: Acid + Metal Carbonate → Salt + Carbon Dioxide + Water+TOPIC+ Alkalis vs BasesSpecification Point 2.38: Know that metal Oxides, Metal Hydroxides and Ammonia can act as bases, and that alkalis are bases that are soluble in water+++ Oxides, Metal Hydroxides & AmmoniaWhat is alkali?Bases that are soluble in water and dissolves to form hydroxide ions OH-----Metal Oxides can act as a base and is soluble in water Metal Oxide + Acid → Salt + Water Example: Metal Hydroxides ----Metal Hydroxides can act as a base and is soluble in water Metal Hydroxide + Acid → Salt + Water Example: Ammonia ----Ammonia can act as a base and is soluble in water Ammonia + Acid → (Ammonium) Salt + WaterAmmonia can act as a base and is soluble in water State the equationAmmonia + Acid → (Ammonium) Salt + Water+TOPIC+ Experiment: Preparation of Soluble Salts (Insoluble reactants)Specification Point 2.39: Describe an experiment to prepare a pure, dry sample of a soluble salt, starting from an insoluble reactant+++ Preparation of Soluble SaltsPreparation of Soluble Salts Using Dilute Acid and Insoluble Base: Describe the method in this experiment (7)1) Add dilute acid into a beaker and heat using a bunsen burner flame 2) Add the insoluble base, a little at a time, to the warm dilute acid and stir until the base is in excess (i.e. until the base stops disappearing and a suspension of the base forms in the acid) 3) Filter the mixture into an evaporating basin to remove the excess base 4) Heat the solution to evaporate water and to make the solution saturated. Check the solution is saturated by dipping a cold, glass rod to the solution and seeing if crystals form on the end. 5) Leave the filtrate in a warm place to dry and crystallise 6) Decant excess solution 7) Blot crystals dry Pic: The filtration of the mixture to remove the excess baseWhat is a suspension?A mixture in which particles can be seen and easily separated by settling or filtration+TOPIC= Experiment: Preparation of Soluble Salts (Acid + Alkali)Specification Point 2.40C (Paper 2C Only): Describe an experiment to prepare a pure, dry sample of a soluble salt, starting from an Acid and AlkaliPreparation of Soluble Salts Using Dilute Acid and Alkali: Describe the method in this experiment (8)1) Use pipette to measure alkali into conical flask and add a few drops of indicator (phenolphthalein or methyl orange) 2) Add acid into burette and note the starting volume 3) Add acid in burette into alkali in flask until indicator changes to appropriate colour 4) Note and record the final volume of acid in burette and calculate the volume of acid added (starting volume of acid - final volume of acid) 5) Add this same volume of acid into the same volume of alkali without the indicator 6) Heat to partially evaporate to leave a saturated solution 7) Leave to crystallise 8) Excess solution is decanted and crystals are blot dry+TOPIC_+ Experiment: Preparation of an Insoluble SaltSpecification Point 2.41C (Paper 2C Only): Describe an experiment to prepare a pure, dry sample of an insoluble salt, starting from two soluble reactants+++ Preparation of Insoluble Salts Using Two Soluble Reactants:How can an insoluble salt be made?An insoluble salt can be made by a precipitation reaction by mixing two soluble salt solutionsWhat is a precipitation reaction?A precipitation reaction is a reaction that produces a precipitatePreparation of Insoluble Salts Describe the method in this experiment (4)1) Dissolve soluble salts in water and mix together using a stirring rod in a beaker 2) Filter to remove precipitate from mixture 3) Wash filtrate with water to remove traces of other solutions 4) Leave in an oven to dry Pic: The filtration of the mixture to remove the precipitate=TOPIC+ Experiment: Preparation of Copper Sulfate from Copper OxideSpecification Point 2.42: Practical: Prepare a sample of pure, dry hydrated Copper (II) Sulfate Crystals starting from Copper (II) OxidePreparation of Pure, Dry Hydrated Copper (II) Sulfate Crystals Acid = Dilute Sulfuric Acid Insoluble Base = Copper (II) Oxide Describe the method for this experiment: (6) State the Equation Of Reaction:1) Add dilute sulfuric acid into a beaker and heat using a bunsen burner flame 2) Add copper (II) oxide (insoluble base), a little at a time to the warm dilute sulfuric acid and stir until the copper (II) oxide is in excess (stops disappearing) 3) Filter the mixture into an evaporating basin to remove the excess copper (II) oxide 4) Leave the filtrate in a warm place to dry and crystallize 5) Decant excess solution 6) Blot crystals dry Equation Of Reaction: Copper (II) Oxide + Dilute Sulfuric Acid → Copper (II) Sulphate + Water CuO (s) + H₂SO₄ (aq) → CuSO₄ (s) + H₂O (l) Pic: The heating of the mixture to leave a saturated solution+TOPIC+ Experiment: Preparation of Lead SulfateSpecification Point 2.43C (Paper 2C Only): Practical: Prepare a sample of pure, dry Lead (II) Sulfate+++ Preparation Of Pure, Dry Lead (II) Sulfate Crystals Soluble Salt 1 = Lead (II) Nitrate Soluble Salt 2 = Potassium Sulfate Describe the method for this experiment: (6) State the Equation of Reaction:1) Dissolve Lead (II) Nitrate and Potassium Sulfate in water and mix together using a stirring rod in a beaker 2) Filter to remove precipitate from mixture 3) Wash residue with water to remove traces of potassium nitrate solution 4) Leave in an oven to dry Pic: The filtration of the mixture to remove the precipitate Equation of Reaction: Lead (II) Nitrate + Potassium Sulfate → Lead (II) Sulfate + Potassium Nitrate Pb(NO₃)₂ (aq) + K₂SO₄ (aq) → PbSO₄ (s) + 2KNO₃ (aq)