Paper 5 Flashcards
Suggest a suitable apparatus to be used when making a large concentration of propanone solution.
a volumetric lask in ranges 25- 250 cm3 volume
When a reaction involving some reactants and a catalyst is to be carried out, in what order should they be added?
The catalyst should be added first
and then the reactants should be added last as adding this would cause the reaction to start.
What is a suitable apparatus to transfer 10 cms from a conical flask?
A 10 cm3 pipette.
Suggest a suitable indicator to be used when the concentration of Iodine in a solution is to be identified.
What will the colour change observed on this indicator be?
A starch indicator will be used.
The iodine on the starch will go from blue-black to colourless.
How could a graph be used to prove that a reaction is in the first order?
- > Find the half-life: if the half-life is constant throughout the graph, then the reaction is first order.
- > Half-life determined from the graph should be constant.
- > Determine the gradient at different points to find the rate. plotting this graph should give a linear plot that goes through the origin of the graph.
Why might there be a large difference in the calculated enthalpy change per mole and the acceptable enthalpy change per mole?
The heat loss will account for the large discrepancy.
