Acids and Bases Flashcards
Lavoisier theory
- acidity caused by presence of oxygen- false
- created word oxygen
Arrhenius theory
- acid- dissociates to form H+ ions
- bases- dissociate to form OH- ions
- dissociate= dissolves in water
Lowry and Bronsted theory
- acid- substance that donates proton (H+) to another species
- base- accepts protons from other species
- allowed gaseous NH3 to be a base
What did the Lowry and Bronsted theory allow for NH3?
to be classified as a base
What to theories do we currently use?
- Arrhenius theory
- Lowry and Bronsted theory
What is a monoprotic acid? Give 2 examples
- acid that only donates 1 mole of protons per mole of acid
- ex- HCl, HNO3
What is a diprotic acid? Give 1 example.
- acid that donates 2 moles of protons per mole of acid
- ex- H2SO4
What is a triprotic acid? Give an example.
- acid that donates 3 moles of protons per mole of acid
- H3PO4
Conjugate acid
species formed from a Broasted-Lowry base by the addition of proton.
Conjugate Base
species formed from a Broasted-Lowry acid by the loss of a proton.
What does the acidity of a solution depend on?
the concentration of H+ ions
What equation is used to find the pH of a solution?
-log10=[H+]
pH values are given to __ decimal places
2
What does the strength of acid refer to?
the pH, not the concentration
What is a strong acid?
- low pH (0 or 1)
- high concentration of H+
- acid fully dissociated into its ions
What is a weak acid?
- high pH (but less than 7)
- concentration of H+ is lower than those in strong acid
- acid not fully dissociated into its ions
What equation is used to calculate concentration of H+?
10^-pH
What is pH on a scale of?
1 to 14
3 ways to measure pH
- pH meter
- universal indicator solution
- universal indicator paper
3 examples of strong acid
- HCl- hydrochloric acid
- HNO3- nitric acid
- H2SO4- sulfuric acid
3 examples of weak acid
- CH3COOH- ethanoic acid
- H2CO3- carbonic acid
- H3PO4- phosphoric acid
What is an alkali?
An alkali is a soluble base
What are acid-base indicators?
chemical detectors that change color according to the concentration of H+ ions
State all indicators.
- methyl orange
- phenolphthalein
- litmus
How can you measure ph?
- methyl orange
- phenolphthalein
- litmus
- pH meter- directly reads H+ concentration
- universal indicator
What is a strong acid?
- dissociates fully and exists entirely as ions in a solution
- good proton donors
- their conjugate bases are not readily able to accept a proton
weak acid
- dissociates only partly
- poor proton donors
- conjugate bases are readily able to accept a proton
- equilibria lies to left in favor of reactants
strong base
- ionize fully
What is acid dissociation written with that base ionization isn’t
equilibria signs
weak base
- ionizes partially
- equilibrium lies to left
acid deposition
the process when acidic compounds in the atmosphere are deposited onto earth
Wet acid deposition
rain, hail, fog, mist, dew: aqueous precipitates
Dry acid deposition
particles in gases, smoke, dust
Where does sulfur oxides come from?
- sulfur dioxide is produced: SO2 when combined with O2
- smelting
- burning coal and fossil fuels
Where do nitrogen oxides come from?
- Nitrogen Oxide (NO) is formed when internal combustion in engines
- nitrogen and oxygen combine
Acid deposition on plant life
- cause leaching- important minerals become soluble and wash away before plants absorb them
- block stomata for gas exchange
- release toxic substances
Acid deposition on water
- eutrophication
- Al3+ become soluble: stop fish’s gills from working
- below 4 pH, rivers are dead
Acid deposition on human health
- not direct
- long term exposure
- increase risk of asthma, bronchitis, emphysema
- irritation of eyes
Responses to SO2 emmisions
- Pre combustion methods
- removing sulfur by crushing coal and washing with water
- hydrodesulfurization- removes sulfur by reacting with Hydrogen, this gas is removed and converted to sulfuric acid - Post- combustion methods
- Flue-gas desulfurization- SO2 neutralized by reaction with CaO and CaCO3 in chimney before released
Responses to NOx emmisions
- Catalytic converters in vehicles
- gas passed over platinum or palladium based catalyst to neutralize product - Lower temperature combustion
- recirculating NO into engine lowers temperature to reduce formation of it
