Chapter 4 Flashcards
What is an acid
Chemical that releases H+ ions in an aqueous solution
Formula of: hydrochloric acid Sulfuric acid Nitric acid Ethanoic acid
HCl
H2SO4
HNO3
CH3COOH
What is dissociation
Splitting of acid to form H+ and an anion
Difference between a strong and weak acid
Strong acid fully dissociates in aqueous solution
Weak acid only partially dissociate
What is the pH of acid affected by
Strength of acid (strong/weak) and its concentration
Difference between strong and weak acid dissociation in equation form
Strong is one direction
Weak acid is a reversible reaction so both direction
Which of these is a weak acid
Hydrochloric, nitric, sulfuric, ethanoic
Ethanoic acid is weak
What is a base
Substance that neutralises an acid to form a salt
What is an alkali
Release OH- when dissolved in water
It is soluble in water and acts as a base
3 alkalis you need to know
NaOH
NH3
KOH
Formula of common bases
Not alkali
(2)
Metal carbonate and metal oxide
Word equation of a neutralisation reaction
Acid + base —> salt + water
Why isn’t the pH of (end products) neutralisation reaction always 7 (neutral)
It depends on volume and concentrations of acids used
As the acid may be limiting or in excess
Products of carbonate and acid
Salt
Water
Carbon dioxide
What is a titration experiment used for
To analyse unknown solutions
How do you ensure titre values are accurate and not a result of random errors
Have concordant results that are similar within a given range and workout its mean titre
How do you make a standard solution
Dissolve a compound of certain mass in water using a volumetric flask so you know its exact concentration
What is an oxidation number
Total number of electrons gained or lost from an atom to form a chemical bond
Oxidation number of Cl2
0
Order of priority in oxidation numbers
Grp 1 and 2 metals, F H O Cl Br I Everything else
What is the sum of oxidation numbers in compound equal to
Total charge
Preferences of oxidation number of following elements Grp 1 Grp 2 F H O Halogens
\+1 \+2 -1 \+1 -2 -1
What is oxidation number usually written as in a compound
In roman numerals in brackets
Which ones has higher priority in halogens for oxidation numbers
Cl or Br
Strength/priority decreases down the group so Cl
Oil
Rig
Stands for
Oxidation is loss…
Reduction is gain…
…of electrons
If oxidation number decreases
Is it reduction or oxidation
Reduction as it has gained electrons
What is disproportionation
When same element is both oxidised and reduced in a chemical process
