Calculate the mass of the sample used in the experiment.
Name apparatus B.
Why does the student wash the residue with distilled water?
What is the colour change of the methyl orange indicator at the end-point?
Give two reasons why the student does three titrations using $25.0\,\text{cm}^3$ of C rather than carrying out one titration using $250\,\text{cm}^3$ of C.
Use the diagrams to fill in the table and work out the mean volume of $0.100\,\text{mol dm}^{-3}$ sodium hydroxide used.
Calculate the number of moles of sodium hydroxide in the average volume of $0.100\,\text{mol dm}^{-3}$ sodium hydroxide used.
Using your answer to (e) and the equation $\text{NaOH} + \text{HCl} \rightarrow \text{NaCl} + \text{H}_2\text{O}$ calculate the number of moles of hydrochloric acid in $25.0\,\text{cm}^3$ of C.
Calculate the number of moles of hydrochloric acid in $250\,\text{cm}^3$ of C.
Calculate the number of moles of hydrochloric acid in $25.0\,\text{cm}^3$ of $1.00\,\text{mol dm}^{-3}$ hydrochloric acid.
Using your answers to both (g) and (h), calculate the number of moles of hydrochloric acid that react with the magnesium carbonate in the sample.
Using your answer to (i) and the equation $\text{MgCO}_3 + 2\text{HCl} \rightarrow \text{MgCl}_2 + \text{CO}_2 + \text{H}_2\text{O}$ calculate the number of moles of magnesium carbonate in the sample.
Calculate the mass of magnesium carbonate in the sample. $[A_r: \text{Mg}, 24; \text{C}, 12; \text{O}, 16]$
Using your answers to (a) and (k), calculate the percentage by mass of magnesium carbonate in the sample.
State whether the average titration volume of aqueous sodium hydroxide would be smaller, larger or unchanged if the conical flask is washed with water and not dried between titrations. Explain your answer.