Calculate concentration in mol dm⁻³ or g dm⁻³ from the amount of solute and the solution volume, rearrange to find moles or volume, handle dilutions, and convert between cm³ and dm³.
(b) A variety of ions are dissolved in the water of the Salton Sea. The concentrations of the major ions are shown in the table below, based on two different sources (both scientific journals). Ion Concentration / , based on Source 1…
(e) The propanoic acid obtained by the distillation was an aqueous solution with a volume of 22.5 . Three 5.00 samples of this solution were titrated with 0.200 to determine the accurate…
Determine the mass of sodium thiosulfate pentahydrate, , needed to prepare 250.0 of a 0.2000 solution.
Explain how the 0.2000 solution is prepared in a volumetric flask from the weighed solid.
Suggest how to prepare 100.0 of a 0.05000 sodium thiosulfate solution from the 0.2000 solution.
Before use, the EDTA solution was standardized against a standard solution of ions. An accurately weighed piece of pure copper wire was dissolved in the minimum volume of concentrated nitric acid and the mixture was warmed gently until no more…
Anhydrous copper(II) chloride, , takes up water vapour from the air, so it cannot be weighed out accurately to make a standard solution. Suggest a laboratory procedure that would remove all of the absorbed water from a sample of solid …
For the AAS method, a series of standards of known concentration was prepared by diluting a stock solution of ions. The instrument was zeroed with deionized water and the absorbance of each standard was recorded. (i) Draw the line of best fit for…
Describe how a standard aqueous solution of potassium manganate(VII) can be prepared from the solid.
Describe the steps by which this standard solution is turned into a calibration curve for the colorimeter.
Explain how the calibration curve is then used to determine the concentration of in a reaction mixture of unknown concentration.
Draw a line of best fit on the graph, extrapolating it beyond the range of the data.
State, in mathematical terms, how the absorbance of these solutions depends on their concentration.
Deduce the equation that relates absorbance to concentration for these solutions, including the numerical value of the constant.
Estimate the absorbance of a 0.400 solution of nickel(II) sulfate.
Predict the difference, if any, between the absorbance of the 0.400 solution read from the extrapolated line and the value calculated from the equation in 3d.
Calculate the mass of solid potassium hydroxide that has to be weighed out.
Describe how the student should prepare this standard solution from the weighed solid using a 250.0 volumetric flask.
The student pipetted 25.00 of the potassium hydroxide solution into a conical flask and titrated it with nitric acid, , of concentration 0.1250 . The burette readings before and after the titration are…
Explain why the potassium hydroxide solution has to be standardized before it is used in the titration. Assume that there are no systematic errors in the procedure.
The student then used the potassium hydroxide solution standardized in 1c to titrate ethanoic acid, , whose concentration was not known. (i) Neutralizing 25.00 of the acid required 40.00 of the standardized…
4.06 g of hydrated magnesium chloride, ( = 203), is dissolved in water to make 0.250 of solution. What is the concentration of chloride ions, in , in this solution? A. 0.0400 B. 0.0800 C.…
A student writing a report on chlorine as a disinfectant collects, from several websites and reference books, values for how much chlorine dissolves in pure water at various temperatures. Source Temperature / °C Solubility of chlorine A 5 1.18 g per 100…
A solution is prepared by dissolving 1.29 g of HA in water and making the volume up to . When the whole of this solution is titrated with sodium hydroxide, NaOH(aq), exactly of the…