Calculate the mass, in g, of solid ethanedioic acid dihydrate ($M_r=126.0$) needed to prepare $250{cm}^3$ of $0.0500{mol\; dm}^{-3}$ standard solution.

The mass of ethanedioic acid dihydrate from Part 1 is dissolved in a beaker containing $80{cm}^3$ of distilled water. Describe how this solution is used to make $250{cm}^3$ of the $0.0500{mol\; dm}^{-3}$ ethanedioic acid solution.

Before the first titration, the $25.0{cm}^3$ pipette is rinsed with a small volume of the $0.0500{mol\; dm}^{-3}$ ethanedioic acid solution. State why it is good practice to rinse the pipette in this way.

Sodium hydroxide solution is added to the burette using a funnel. State why it is good practice to remove the funnel from the burette before the titration.

In a different experiment, $1.42g$ of solid ethanedioic acid dihydrate is used to make $250{cm}^3$ of standard ethanedioic acid solution. $25.0{cm}^3$ of this solution reacts with exactly $23.15{cm}^3$ of sodium hydroxide solution. The equation for the reaction is: $H_2{C}_2{O}_4(aq)+2NaOH(aq)\to {Na}_2{C}_2{O}_4(aq)+2H_{2}O(l)$ Calculate the concentration of the sodium hydroxide solution. Give your answer to 3 significant figures.

The uncertainty in the $25.0{cm}^3$ of solution from the pipette is $\pm 0.05{cm}^3$. The total uncertainty in the $23.15{cm}^3$ of solution from the burette is $\pm 0.10{cm}^3$. Calculate the total percentage error in using the pipette and burette. Give your answer to 2 significant figures.