Solutions, Acids, Bases & pH. Solute –substance whose particles are dissolved in a solution ie....
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Transcript of Solutions, Acids, Bases & pH. Solute –substance whose particles are dissolved in a solution ie....
Solutions, Acids,
Bases & pH
Solute –substance whose particles are dissolved in a solution
ie. salt, sugarSolvent – the substance in
which the solute dissolvesie. water “universal
solvent”
Dispersion of Sugar in Water
Conductivity – ability to conduct electricity
Freezing point – decreases Boiling point – increases Heat of solution – energy is
absorbed or released during the formation of a solution Energy released = exothermic Energy absorbed = endothermic
Properties of Liquid Substances
Surface area – ↑ surface area = ↑ rate
Stirring – moves dissolved particles away from the solid
Temperature – ↑ temperature = ↑ rate
Factors Affecting Dissolving Rate
Factors Affecting Dissolving Rate
One of the most important aspects of a living system is the degree of acidity or alkalinity
Ionization of water -breaking apart water molecules into ions of opposite chargeHOH + HOH H3O+ +
OH-
(water) (water) (hydronium)
(hydroxide)
Acid – ionic compound that produces hydronium ions (H3O+) when dissolved in water
Stronger acid = more hydronium ions Number of hydronium ions in solution is greater than the number of hydroxide ions
AcidsAcidsAcidsAcidsCharacteristics of Acids
• Tastes sour• Reacts strongly with metals• Conducts electricity in water• Turns blue litmus paper red• Generally clear solutions• Proton donors (give H+)
Examples of AcidsVinegar H2SO4
Citrus fruits HNO3
Stomach acid (HCl)
Acetic acid CH3COOH Vinegar
Carbonic acid H2CO3 Carbonated beverages
Hydrochloric acid HCI Digestive juices in stomach
Nitric acid HNO3 Fertilizer production
Phosphoric acid H3PO4 Fertilizer production
Sulfuric acid H2SO4 Car batteries
Add Base to Water
OH-
OH-OH-
OH-
OH-OH-
OH-
OH-
Na+
Na+Na+
Na+Na+
Na+
Na+
Na+
NaOH Na+ + OH-
Base – ionic compound that produces hydroxide ions (OH-) when dissolved in water
Stronger base = more hydroxide ions Number of hydroxide ions in solution is greater than the number of hydronium ions
BasesBasesBasesBasesCharacteristics of Bases
• Tastes bitter• Reacts strongly with metals• Conducts electricity in water• Turns red litmus paper blue• Generally slippery feel• Proton acceptors (take H+)
Examples of BasesLye (NaOH) Ca(OH)2
Ammonia (NH3) KOH
Aluminum hydroxide Al(OH)3 Deodorant, antacid
Calcium hydroxide Ca(OH)2 Concrete, plaster
Magnesium hydroxide Mg(OH)2 Antacid, laxative
Sodium hydroxide NaOH Drain cleaner, soap production
NeutralizationNeutralizationReaction between an Acid & Base
that forms salt & water
HCl + NaOH HOH + NaCl(Hydrochloric Acid) + (Sodium Hydroxide) (Water) + (Salt)
Sodium chloride NaCl Food flavoring, preservative
Sodium carbonate Na2CO3 Used to make glass
Potassium chloride KCl Used as a salt substitute to reduce dietary intake of
sodiumPotassium iodide Kl Added to table salt to
prevent iodine deficiency
Magnesium chloride MgCl2 De-icer for roads
Calcium carbonate CaCO3 Chalk, marble floors, and tables
Ammonium nitrate NH4NO3 Fertilizer, cold packs
Remember!!During a chemical reaction:
Bonds are broken Elements are rearranged New compounds are formed
Balanced Equation - # of atoms of each element are equal on both sides of a chemical equation Reactants are shown on the left
Products are shown on the rightHCl + NaOH H2O + NaCl
Reactants Products
pH ScaleMeasure of hydronium (H3O+) ion
concentration pH affects the physical & chemical properties
of a substance
Acid – pH = 0-6
Neutral – pH = 7Neutral – pH = 7 Base – pH
= 8-14
A change of one pH unit changes the H+ concentration by a factor of 10.
A change of 1 pH unit changes the H3O+ concentration by a factor of 10
ie. pH 1 has ie. pH 1 has 10x more 10x more hydronium hydronium ions than pH ions than pH 2; 100x more 2; 100x more than pH 3, than pH 3, etc. etc.
Why do we need to know pH?
IndicatorChanges color as the pH changes
• Indicates the pH of the solution
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Works Cited