PAPER 1 - PRACTICALS Flashcards
method of energy changes practical - 8 steps
- add acid to polystyrene cup
- record start temp of solution with thermometer in a hole in the solution
- add the other reactant to the cup
- add a lid and stir the soltuion
- record the highest/lowest temp
- calulate the temp change
- repeat steps to find anomalies and mean
- repeat steps 1-7 with different test solutions (the thing you add to the acid)
what is the polystyrene cup practical used to measure
energy changes
what equipment do you need for the energy change practical
polystyrene cup - good insulator that reduces energy transfer to the surroundings
lid with hole - reduces energy transfer to surroundings
thermometer - measure temperature
balance - measure mass
measuring cylinder - volume
stick to stir
what different reactants could be used when doing the temp change practical
- acid and metal
- acid and metal carbonate
- neutralisation reaction - acid and base
- displacement reaction - reactive metal and non reactive
how would you use the energy change practical to find the reactivity of a metal
- investigate the temp change
- more reactive metal - greater temp change
whats the titration practical used to measure
the volume of an acid or alkali that would neutralise an unknown acid or alkali
method of titration - 8 steps
- add acid/base to conical flask - known volume with PIPETTE
- add indicator to conical flask and swirl to mix
- stand flask on white tile
- fill burette with acid/base - you dont know how much so j fill with loads but record this volume
- add drops of acid/base in burette and swirl everytime
- stop when colour change
- measure the volume of the burette and find the difference - this is how much it took to neutralise
- repeat
what questions have been asked in the past with titration
- what v of citric acid need to neutralise sodium hydroxide
- what v of sulphuric acid need to neutralise sodium hydroxide
- what v of sodium hydroxide need to neutralise rainwater
HYDROXIDE - ALKALI
ACID - ACIDIC
RAIN WATER - ACIDIC
for titration - which acid/base goes in the burette and which goes in the conical flask
KNOWN volume — CONICAL FLASK
UNKNOWN volume — BURETTE
what colour is phenolphthalein in acid/alkali
colourless - acid
pink - alkali