Which contains the analyte ultimately gravimetric methods can define as quantitative methods which is based on the determining determination of the mass of a pure compound to which the analyte is chemically related there are mainly two types of gravimetric analysis precipitation and volatilization in precipitation method analyte must be converted to a solid that means precipitate by different different appropriate precipitating agent the precipitate from the solution is then filtered washed and purified.
It is way while in a volatilization method the analyte is decomposed to a product ultimately volatilized product or dried product and which is then collected and weight or alternatively the mass of the volatilized product is determined indirectly by the loss of mass of the sample in general gravimetric analysis is the method in which the constituent is measured or constituent which we want to measure is converted into other constituents of known composition and which is stable and can easily purified and wait that means we are converting a component into a known substance.
Then it is purified and wait for example determination of iron in the solution so first iron is converted into a known substance that is ferric hydroxide then the spheric hydroxide is dried and weighed in a weight as a ferric oxide now let’s discuss the steps for the gravimetric analysis these are the steps for the gravimetric analysis preparation of solution precipitation digestion filtration washing drying or ignition weighing and calculation , discuss preparation of analyte solution in a gravimetric analysis usually involves the precipitation of analyte from a solution so first step includes sampling that means representative of bulk the second step prepare the analyte solution.
Dissolution so for that you need preliminary separation to separate potential interference before precipitating an ally for that adjustment of solution condition is needed that means to maintain low solubility of precipitate and maximum precipitate formation for example calcium oxalate is insoluble in basic medium so by adjusting ph temperature volume or the concentration of test substance you will get a very less solubility of precipitates the next step is precipitation process the precipitating reagent is added at a concentration that favors the formation of a good precipitate this may require less concentration and extensive heating or careful control of the large excess of precipitation that should be avoided.
Increases the chance of adsorption on a precipitate formed precipitate the next step includes digestion of the precipitates that is the most important part a formed precipitate allowed to stand in contact with the mother licker what is mother licker the solution which from which it was precipitated this process is called digestion or osteoarthritis the small particle tends to dissolve and precipitate on the surface of larger crystals digestion make larger crystals and reduces surface contamination and reduces crystal in perfection now in our next step we are separating a precipitate from the mother liquor that is called filtration.
Nature of precipitate and even cost of media and the heating temperature required for the drying so this are the filtering medium this are the filtering medium we can use for filtration process we can use filter paper filter pulp filter mats crucible that is fitted with a porous plate after filtration co-precipitated impurity especially those on the surface which is removed by washing the precipitate a wet precipitate with mother liquor and which will also be removed by washing so here at this tape you need to add electrolyte to wash liquid because some precipitate cannot be washed with pure water and peptidation occurs for example for the precipitates of silver chloride.
We need washing with nitric acid next step is trying to remove solvent and wash electrolytes we need this drying technique it is done by heating at 110 to 120 degree celsius for one to two hours that will convert your hydroscopic compound to non-hygroscopic compound so this technique may use high temperature if precipitate must be converted to a more suitable form before weighing right so we uh this condition depends on a type of component which we are analyzing right uh that depends on a component characteristic if it is stable at a higher temperature then we can use high temperature but if it is degraded then we have to use up to 10 20 degree celsius the next step is vein after the precipitate is allowed means after the drying process over allow your precipitate to cool down and then it is weighed in a crucible a properly calibrated analytical balance should be used so after uh weighing uh from the weight of the precipitate form in a gravimetric analysis we can calculate the weight of the analyte so this is all about the steps of gravimetric analysis