acids and bases

What is a strong acid?

An acid that dissociated completely in solution releasing H+ ions

What is a weak acid?

An acid that dissociated only partially in solution, releasing H+ ions

What is an alkali?

A type of base that dissolves in water forming hydroxide ions

What is a base?

A compound that neutralises an acid to form a salt

What is a salt?

The product of a reaction in which the H+ ions from the acid are replaced by metal or ammonium ions

What is the definition of a neutralisation reaction?

A chemical reaction in which an acid and base react together to form a salt

What is the formula for hydrochloric acid? Is it strong or weak?

HCL - strong

What is the formula for sulphuric acid? Is it strong or weak?

H2SO4 - strong

What is the formula for nitric acid? Is it strong or weak?

HNO3 - strong

What is the formula for ethanoic acid? Is it strong or weak?

CH3COOH - weak

What is the formula for Sodium hydroxide ? Is it strong or weak?

NaOH - strong base

What is the formula for potassium hydroxide? Is it strong or weak?

KOH - strong base

What is the formula for ammonia? Is it strong or weak?

NH3 - weak base

How come ammonia is a base?

It forms a dative covalent bond with water forming NH4+ and therefore OH- is released as a result of

What is the formula that links n,c and v?

N = c x v

Why do you rinse the apparatus before titration?

To avoid contamination

How do you fill the burette titration?

Using a funnel, remove the funnel afterwards

How do you record the initial burette reading?

At eyelevel measuring the bottom of the meniscus

How do you fill up the Conical flask in titration?

Use a pipette and filler to accurately measure a volume

Which indicators do you use in titration and why?

Either phenophalien or methyl orange because it needs to be one that has a distinct colour change

When is the endpoint indicated?

When the colour changes (phenophalein = pink to colourless and methyl orange = red (acid) yellow (alkali) to orange)

How do you repeat the experiment to get a mean titre?

Until concordant results are obtained and then you calculate the mean of the concordant results

What are all metal oxides and metal carbonates and why?

They are all bases. Because they react with acids to form salt and water (and carbon dioxide for carbonates).
This shows they neutralize acids

How can you tell when something is an acid

It starts with H or ends with a carboxylic acid

How can you tell when something is an insoluble base

Contains O²⁻ or OH⁻ with a metal, but not soluble in water.v

How you tell when something is an alkali

Metal hydroxide from Group 1 or 2, or ammonia.

How can you tell when something is a salt

No H⁺ or OH⁻ — it's the product of acid + base

What is the product of an acid + alkali

Salt + water

What is the product of an acid + metal oxide

Salt + water

What is the product of an acid + metal carbonate

salt + water + carbon dioxide

What is the product of an acid + metal

salt + hydrogen

How do you convert mol dm-3 into g dm-3

Multiply by mr

What is the equipment used

Beaker, burette, volumetric pipette, conical flask, volumetric beaker

what is a standard solution

a solution with a known concentration

what is a titre?

the volume added from the burette when the volume of one solution has exactly reacted with another solution

what is a mean titre?

the average of all concordant titration results, which are within a set tolerance of each other - usually 0.10cm3

when do you use the mean titre?

for subsequent calculations

what do you use titrations for

to work out unknown information about an unknown substance

what are the 4 key steps for identifying a unknown substance using titration

1- prepare a solution of an unknown substance in a volumetric flask
2- using a pipette and pipette filler measure 25cm3 of the prepared substance in a conical flask
3-using a funnel, fill a burette and titrate the solution using a known conc of solution
4-analyse results

what does DMEMA stand for

D- data - storyboard
M-moles of available data
E - equation mol ratio
M - moles of unknown solution
A- answer

what stays the same as you transfer from the conical to the volumetric flask and what differs

the concentration of the solution will stay the same but the number of mols will differ