Chapter 4 Acids and Redox Flashcards
What is an Acid
- Contain Hydrogen
- PH<7
- Release H⁺ ions into the solution when dissolved in water
Show Hydrochloric Acid dissociating in water
HCl → H⁺₍ₐᵩ₎ + Cl⁻ ₍ₐᵩ₎
What is a strong acid
A strong acid completely dissociated in an aqueous solution
What is a weak acid
A weak acid partially dissociates in an aqueous solution
Name 2 strong acids
Hydrochloric Acid
Nitric Acid
Name a weak acid
Ethanoic Acid
What is the formula for Hydrochloric Acid
HCl
What is the formula for Sulfuric Acid
H₂SO₄
What is the formula for Nitric Acid
HNO₃
What is the formula for Ethanoic Acid
CH₃COOH
Show Ethanoic Acid dissociating (partially) in an aqueous solution
CH₃COOH₍ₐᵩ₎ ⇌ H⁺₍ₐᵩ₎ + CH₃COO⁻₍ₐᵩ₎
How does Sulphuric Acid behave
Dissociation happens in 2 steps
Show the dissociation of Sulfuric Acid
- First behaves like a strong acid
H₂SO₄₍ₐᵩ₎ → H⁺₍ₐᵩ₎ + HSO₄⁻₍ₐᵩ₎ - Then the HSO4- ions behave as a weak acid
HSO₄⁻₍ₐᵩ₎ ⇌ H⁺₍ₐᵩ₎ + SO₄²⁻₍ₐᵩ₎
What is a base
A base neutraises an acid to form a salt
Give examples of bases
Generic
- Metal Oxides
- Metal Carbonates
- Metal Hydroxides
- Alkalis
What is an Alkali
An Alkali is a base that dissolves in water releasing OH⁻ ions
Acid + Alkali →
Salt + Water
HCl₍ₐᵩ₎ + NaOH₍ₐᵩ₎ →
Acid + Alkali
NaCl₍ₐᵩ₎ + H₂O₍ₗ₎
Ionic equation of
HCl₍ₐᵩ₎ + NaOH₍ₐᵩ₎ → NaCl₍ₐᵩ₎ + H₂O₍ₗ₎
H⁺₍ₐᵩ₎ + OH⁻₍ₐᵩ₎ → H₂O₍ₗ₎
Metal oxide/hydroxide + acid →
What is the observation
salt + water
Solid Metal Oxide Disappears
Metal hydroxide + acid →
salt + water
H₂SO₄₍ₐᵩ₎ + MgO₍ₛ₎ →
Acid + Metal Oxide
MgSO₄₍ₐᵩ₎ + H₂O
Ammonia + Acid →
Ammonium salts containg an ammonium ion
Carbonate + acid →
salt + water + carbon dioxide
What is a titration
A technique used to accurately measure the volume of one solution that reacts exactly with another solution
What are titrations used for
- Finding the concentration of a solution
- Identification of unknown chemicals
- Finding the purity of a substance
What are concordant results
Results within 0.10 cm^3 of each other
Ammonia + Acid →
Salt containing an ammonium Ion
How do you prepare a standard solution
(e.g. NaOH)
- Find mass of solid you want
- Dissolve solid in a beaker using less distilled water than needed
- Transfer to volumetric flask and rinse with distilled water
- Fill up to the graduation line with distilled water
- Invert the flask several times to mix
Evplain the effect of adding too much distilled water to the standard solution
The solution will be too dilute
What is a standard solution
A solution of known concentration
What is the oxidation number for any element
0
In a compound, what is the oxidation number for
Group 1 Elements
+1
In a compound, what is the oxidation number for
Group 2 Elements
+2
In a compound, what is the oxidation number for
F
Fluorine
-1
In a compound, what is the oxidation number for
H
Hydrogen
+1
-1 in metal hydrides eg NaH or MgH₂
In a compound, what is the oxidation number for
O
Oxygen
-2
-1 in Peroxides (H₂O₂)
+2 in Oxygendifluorides (OF₂)
In a compound, what is the oxidation number for
Cl
Chlorine
-1
Except when combined with O or F
What is the uncertainty of a burette?
0.05
What do the roman numerals next to an element tell you
The oxidation number of the element
What is a redox reaction
A reaction involving both reduction and oxidation
Metal + Acid →
Salt + Hydrogen
