State the names of the three pieces of apparatus labelled A, B and C.
The student measures $5.0\,\text{cm}^3$ of the vinegar into apparatus C and makes it up to $250\,\text{cm}^3$ with distilled water. Apparatus A is filled with $0.0250\,\text{mol dm}^{-3}$ sodium hydroxide. For each titration, $25\,\text{cm}^3$ of the diluted vinegar is poured into apparatus B using a measuring cylinder. A few drops of methyl orange indicator are then added.
From the values shown, record the starting and ending readings, then work out the volume of $0.0250\,\text{mol dm}^{-3}$ sodium hydroxide used in titration 4.
Complete the results table by working out the volume of $0.0250\,\text{mol dm}^{-3}$ sodium hydroxide used in titrations 1 and 3.
In the results table, place ticks (✓) beside the best titration values and use them to work out the average titre.
Suggest an improvement to the method that would make the results more accurate. Explain your answer.
A second student records an average titre of $18.4\,\text{cm}^3$. The reaction is $\text{CH}_3\text{COOH} + \text{NaOH} \rightarrow \text{CH}_3\text{COONa} + \text{H}_2\text{O}$. Calculate the amount of substance of $0.0250\,\text{mol dm}^{-3}$ sodium hydroxide used.
Calculate the amount of ethanoic acid, in moles, contained in the $25\,\text{cm}^3$ portion of diluted vinegar that was transferred into apparatus B for each titration.
The diluted vinegar solution is prepared by diluting the original $5.0\,\text{cm}^3$ of vinegar up to $250\,\text{cm}^3$ with distilled water. Calculate the number of moles of ethanoic acid in the original $5.0\,\text{cm}^3$ vinegar sample.
Calculate the concentration, in $\text{mol dm}^{-3}$, of ethanoic acid in the original vinegar sample.