Core Practicals Chemistry

Core Practical 1 - measure the molar volume of a gas

find volume of CO2 produced when you react acid and a carbonate

CP1 - what reagents

calcium carbonate (CaCO3) and ethanoic acid

CP1 - equipment required

gas syringe or upturned measuring cylinder

conical flask

bung

CP1 - data analysis

vary mass of CaCO3, plot a graph

1:1 ratio so find moles of CO2 compared to volume

scale up to 1 mol

should be around 24

CP1 - key points

weigh by difference

reduce escaping gas by putting CaCO3 in a small container in the flask and tipping to combine

CP1 - issues

CO2 is slightly soluble in water, some might dissolve

escaping gas

Core practical 2 - prepare a standard solution from a solid acid and use it to find the concentration of a solution of sodium hydroxide.

prepare a standard solution of sulfamic acid, then titrate with the NaOH

CP2 reagents

sulfamic acid NH2SO3H solid

dilute with water

NaOH solution of unknown concentration

CP2: steps

1. weigh by difference, find mass of sulfamic acid
2. add to volumetric flask, rinse everything it touches into the flask
3. fill with water up to the line (meniscus)
4. cap on and shake
5. put this into the burette and titrate with the NaOH
6. find the mean titre
7. find mols of sulfamic acid required
8. 1:1 ratio - mols of NaOH in solution - conc

Core practical 3 - find the concentration of a solution of hydrochloric acid

titrate against NaOH


1. rinse everything with H2O then reactant
2. use pipette for NaOH (known concentration) and transfer to flask
3. burette filled, normally with acid
4. add some titrant, swirl, read titre
5. repeat until concordant
6. do a rough titre first and don’t include in concordance
7. calculate mean titre