What kind of reaction is shown by the temperature increase?
Plot the maximum temperature increase against the mass of $M$, then draw two intersecting straight lines through the points.
Use your graph to determine the mass of $M$ needed to give a maximum temperature increase of $5.0^{\circ}\text{C}$.
Use your graph to determine the maximum temperature increase if $1.5\,\text{g}$ of $M$ is used.
Calculate the number of moles of copper(II) sulfate in $25.0\,\text{cm}^3$ of $2.7\,\text{mol dm}^{-3}$ aqueous copper(II) sulfate.
Use your graph to work out the mass of $M$ that would react completely with $25.0\,\text{cm}^3$ of $2.7\,\text{mol dm}^{-3}$ aqueous copper(II) sulfate.
Apply the equation $M + \text{CuSO}_4 \rightarrow \text{MSO}_4 + \text{Cu}$ and your answers to (d)(i) and (d)(ii) to find the relative atomic mass of metal $M$.