Researching Chemistry Flashcards
what is weighing by difference?
the most accurate way to measure the mass of reactants and products
describe weighing by difference:
The accurate mass of a weighing boat is first weighed empty and then the sample is added to it.
The accurate mass of the weighing boat and its contents are then measured and recorded.
The contents of the weigh boat is then transferred to be used in the experiment.
The empty weigh boat is reweighed and the mass is recorded.
The accurate mass of the sample transferred is the difference between the two recorded masses.
what does a desiccator do?
Used to store dried samples in a dry atmosphere. It contains desiccant in its base which acts as a drying agent by absorbing the moisture.
what is vacuum filtration?
a technique used for separating a solid product from a liquid.
describe vacuum filtration:
carried out under reduced pressure and is faster than other methods of filtration.
The mixture is poured through filter paper into a Buchner funnel, the solid is trapped by the filter and the liquid is drawn through the funnel into the flask below by vacuum
what is refluxing?
allows a chemical reaction mixture to be heated without volatile substances escaping
what is distillation?
a technique used to purify and identify organic compounds
what is solvent extraction?
involves isolating a solute from a liquid mixture or solution by extraction using an immiscible solvent in which the solute is soluble.
what is recrystallisation?
used to purify a an impure solid
what technique can be used to identify a pure compound?
melting point analysis
