Acids and Bases Flashcards
Define Acid
substances that produce H⁺ ions
Name 3 examples of acids
H₂SO₄ , HNO₃ , HCl , H₃PO₄
Fill in the blanks:
In solutions, acids produce a pH ___ at rtp.
< 7
Are Non-metal oxides acids or bases?
acids
What happens when an acid dissociates?
it produces H⁺ ions which is what makes a solution acidic.
What happens when a non-metal oxide reacts with water?
forms an acid
Where do acids produce H⁺ ions?
ONLY IN WATER
Why is HCl either an acid or neutral depending on the type of bonding it has?
If HCl has ionic bonding, it can dissolve in water, therefore dissociating to release H⁺ ions which is what makes a solution acidic.
If HCl has covalent bonding, it is insoluble in water so no H⁺ ions can be released because they can dissociate.
Define bases
substances that react with acids to form water
What ion do most bases produce in water?
OH⁻
Define neutralisation reaction
when an acid and a base react to produce water
acid + base →
salt + water
NH₃ + H₂O →
NH₄OH (ammonia)
NH₄OH → (dissociated)
NH₄ + OH⁻
Define alkali
base which dissolves in water, specifically group 1 metal hydroxides / carbonates
What does the pH >7 (if the base dissolves) measure?
the concentration of acids / bases
Define Ionic equation
an equation that only shows the change in chemicals
What has to happen in order for a neutralisation reaction to react a pH of 7?
the acid and the base have to react in equal molar quantities (H⁺ + OH⁻)
What is the logarithmic scale for pH?
The scale where e.g. pH 3 is ten times more acidic than pH 4 and pH 3 is 100 times more acidic than pH 5. Likewise, pH 11 is 10 times more basic than pH 10.
THE PH DOES NOT DIRECTLY RELATE TO THE DANGER OF AN ACID/BASE
ok…
What does concentration measure?
the moles of a substance dissolved in a specific volume of solvent (water)
What is the unit of concentration?
mol / dm³ ⤵
↓ volume
moles of
of solvent
solute
1 dm³ =
1,000 cm³
Fill in the blanks: The concentration of an acid is a measure of the _____________________ dissolved in any solvent.
number of moles
What is the difference between the strength of an acid and the concentration of an acid?
The concentration of an acid is a measure of the number of moles dissolved in any solvent. Any acid can have any concentration.
The strength of an acid is an inherent / fixed property of an acid.
What does the strength of an acid measure?
the degree of dissociation
stronger acid =
= higher degree of dissociation
Pick the correct word:
- Stronger / Weaker acids effervesce more and faster and have a higher temp. increase when reacting with a metal.
- Stronger / Weaker acids effervesce more and faster and have a slight higher temp. increase when reacting with a metal carbonate.
- When reacting with metal hydroxides, the temp. increases less in stronger / weaker acids .
a) When testing for electrical conductivity, H₂ effervesces at the cathode and Cl₂ effervesces at the anode (5 amps) in stronger / weaker acids.
b) H₂ effervesces at the cathode and Cl₂ effervesces at the anode (1 amps) in stronger / weaker acids.
- Stronger
- Stronger
- Weaker
- a) stronger
b) weaker
Fill in the blanks:
During conduction, ions are ________ and then replaced by _____________________. ask mr.bow
During conduction, ions are used up and then replaced by the undissociated molecules.
Define titration
the method used to accurately measure the concentration of a solution
What does a volumetric pipette do?
accurately measures (only) one volume (unknown chemical)
What does a burette do?
less accurately measures any volume, can add chemicals in small sections (known chemical)
What is the general method for titration?
1) clean pipette with water
2) clean pipette with intended solution
3) measure 25cm³ of NaOH into conical flask
4) add indicator (2 drops)
5) clean burette with water
6) clean burette with HCl
7) fill burette and write down initial reading
8) add HCl (little bit at a time) until HCl goes colorless
9) repeat until concordant results (within 0.1 cm³)
