Transcript Acids, Bases, & Salts

Acids, Bases, & Salts
I.Acids, Bases & Salts
• In water, acids produce H+
(hydrogen ions/proton)
Hydrogen ions/protons can also be called
hydronium ions (H3O+)
How hydronium ions are formed:H+ + H2O → H3O+
Draw the electron dot structures:
Common Acids:
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ethanoic acid (vinegar)
citric acid in lemons
sulfuric acid
hydrochloric acid
•
In water, bases produce
OH- (hydroxide ions)
Ex: NaOH (s) → Na+ (aq) + OH- (aq)
Common Bases
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•
•
•
soap
sodium hydroxide
ammonia
aluminum hydroxide (Al(OH)3) antacid in
Maalox
•A salt is an IONIC substance formed
from a (+) metallic or polyatomic ion
and a (-) ion (NOT hydroxide)
•Ex: calcium carbonate_________
magnesium bromide_________
ammonium chloride__________
sodium chloride_____________
Draw electron dot:
• Draw electron dot:
• Magnesium bromide
• Sodium Chloride
II. Comparing/contrasting Acids
and Bases
Acids
Bases
Definitions
*Arrhenius (most common)
A substance that produces
hydrogen (H+) or hydronium
(H3O+) ions as the only
positive ion in solution
A substance that produces
hydroxide (OH-) ions as the
only negative ion in solution
Alternative definition*
A proton (+) DONOR
A proton (+) ACCEPTOR
General formula
H-metal
Metal-OH
Properties
-react with metals to
produce H2 gas
-react with bases to form
salt and water
-react with acids to form a
salt and water
Electrolytes!! Conduct electricity because they have moving ions
Acid/base continued
Acid
Base
Reactions
acid+ metal →H2 (g) + salt
Acid + base → water + salt
Base + acid → water + salt
pH
Low (0 to 7)
High (7-14)
Ratio of H+ to
OH-
Lots of H+ or H3O+: little OH-
Little H+ or H3O+ : Lots of OH-
Strength
Strong acid ↔ weak acid
0
to 6
Weak base ↔ strong base
8
to 14
Identifying acids, bases, salts based on the formula
Acids
Bases
Salts
Not Acids, bases, or
salts
These are ALCOHOLS
CH3COOH –
ethanoic acid
HCl – hydrochloric
acid
H2SO4- sulfuric acid
NH3- ammonia
NaOH- sodium
hydroxide
Ca(OH)2 – calcium
hydroxide
NaF- sodium
fluoride
KCl –
potassium
chloride
(NH4)2NO3ammonium
nitrate
CH3OH – methanol
CH3CH2OH – ethanol
CH3CH2CH2OH propanol
-Have H at
beginning or end
of the formula
-Other elements
are Non metals
*NH3 is an
exception
-Have OH at end of
formula
--other element
metal
-metal and
non metal
-NH4+ +
nonmetal
-OH end
- C and H in the rest of
the formula
-Electrolyte
-Electrolyte
-Electrolyte
-Do NOT conduct elec
The exception to these rules: organic acids
(organic means contains carbon)
 End In COOH
Have a different set of naming rules that we
will learn in Organic Chemistry
Ex: CH3COOH ethanoic acid
Doesn’t start with an H but it is still an
acid
• http://www.sasked.gov.sk.ca/branches/elearni
ng/tsl/resources/subject_area/science/chem_
30_resources/lesson_8/acids_and_bases.shtm
l (acids donate H+, bases accept H+)
• Strong vs. weak acid animation
http://www.chembio.uoguelph.ca/educmat/c
hm19104/chemtoons/chemtoons1.htm
Phosphoric acid is added to
soft drinks to give them a
sharper flavor. It also
slows the growth of molds
and bacteria, which would
otherwise multiply rapidly in
the sugary solution.
Original
Tooth
After
24 hours
After
1 week
After
1 month
After
3 months
Acid rain…a “bad acid”
What causes it?
burning fossil fuels
Damages
buildings
plants
aquatic animals
Environmental Effects of Acid Rain on Lake and Stream Ecosystems
ALL fish die (4.2)
Healthy lake (6.5)
Frog eggs, tadpoles, crayfish,
and mayflies die (5.5)
Rainbow trout begin to die (6.0)
“Acid Buildup in Oceans Threatens Food Chain”
What do a sprinter and yogurt have in common?
Lactic Acid!
Which of the following are bases?
CH3COOH
NH3
HCl
HC2H3O2
Ca(OH)2
KCl
NaF
CH3CH2OH
Do you want to see me break a penny with
my bare hands?
How did this happen?
• Rub opposite edges of a penny made after 1984
with sandpaper to expose the zinc on the inside
• Soak in hydrochloric acid
• Rinse penny in sodium hydroxide solution
• Rinse the penny in water
• Place in ethanol (alcohol)
• Let it dry and RIP!
Using the equation on Reference Table T, you can
solve for either the unknown molarity/
concentration (M) OR the volume (V) of base
needed to neutralize an acid
= molarity of H+
= volume of acid
= molarity of OH–
= volume of base
Ex 1: A 25.0-milliliter sample of HNO3 (aq) is
neutralized by 32.1 milliliters of 0.150 M KOH
(aq). What is the concentration of the acid?
Ex 2: How many milliliters of 0.200 M NaOH are
needed to neutralize 100. mL of 0.100 M HCl?