Calculate the mass of the scrap iron.
The iron is put into a conical flask and excess dilute sulfuric acid is added. The flask is warmed, and the iron reacts with the sulfuric acid to form $\text{Fe}^{2+}$ ions. Suggest why the flask is warmed.
A gas is given off during the reaction. Name the gas.
Give a test and observation to identify this gas.
Once all of the iron has reacted, the solution is cooled and then made up to $250\text{ cm}^3$ with distilled water. This is solution S. In which apparatus should S be prepared?
$25.0\text{ cm}^3$ of S is transferred into a conical flask. Which apparatus should be used to move $25.0\text{ cm}^3$ of S into a conical flask?
Solution T is $0.0200\text{ mol dm}^{-3}$ potassium manganate(VII). Aqueous potassium manganate(VII) is purple. A burette is filled with T. T is added to the conical flask containing S until the end-point is reached. What colour is the solution in the flask at the end-point? Explain your answer.
The student carries out three titrations. The diagrams show the burette liquid levels at the start and finish of each titration. Use the diagrams to complete the results table. Tick the most suitable titration results. From these results, the average volume of T needed is [BLANK] $\text{cm}^3$.
Calculate the number of moles of potassium manganate(VII) in the average volume of T required. T is $0.0200\text{ mol dm}^{-3}$ potassium manganate(VII).
Five moles of $\text{Fe}^{2+}$ react with one mole of potassium manganate(VII). Calculate the number of moles of $\text{Fe}^{2+}$ in $25.0\text{ cm}^3$ of S.
Calculate the number of moles of $\text{Fe}^{2+}$ in $250\text{ cm}^3$ of S.
Calculate the mass of $\text{Fe}^{2+}$ in $250\text{ cm}^3$ of S. $[A_r: \text{Fe}, 56]$
Using your answers to (a) and (j), calculate the percentage purity of the scrap iron sample.