The sample is first put into a beaker that has already been weighed, and the beaker is then weighed again. Mass of beaker + sample $= 51.23\,\text{g}$. Mass of beaker $= 49.86\,\text{g}$. Calculate the mass of the sample used in the experiment.
Name the apparatus $A$.
What safety item should be used with apparatus $A$?
Why should the safety item be used?
Name the apparatus $B$.
Why does the student rinse out the beaker with distilled water and then transfer the washings to apparatus $B$?
Why does the student choose apparatus $A$ rather than a measuring cylinder to transfer $25.0\,\text{cm}^3$ of $C$ into the conical flask?
What colour change does the methyl orange indicator show at the end-point? The colour changes from [BLANK] to [BLANK].
Use the diagrams to fill in the table, tick the best titration results, and calculate 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 in (e).
Using your answer from (f) 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 present in $250\,\text{cm}^3$ of $C$.
Calculate the number of moles of hydrochloric acid in $25.0\,\text{cm}^3$ of $2.00\,\text{mol dm}^{-3}$ hydrochloric acid.
Using your answers to both (h) and (i), calculate the number of moles of hydrochloric acid that react with the calcium hydroxide in the sample.
Using your answer to (j) and the equation $\text{Ca(OH)}_2 + 2\text{HCl} \rightarrow \text{CaCl}_2 + 2\text{H}_2\text{O}$, calculate the number of moles of calcium hydroxide in the sample.
Calculate the mass of calcium hydroxide in the sample. [$A_r$: Ca, $40$; O, $16$; H, $1$]
Using your answers to (a) and (l), calculate the percentage by mass of calcium hydroxide in the sample.
State and explain whether the average titration volume of sodium hydroxide would be smaller, larger or unchanged if $3\,\text{cm}^3$ of methyl orange indicator was used instead of three drops.