(i) Loss in mass: «8.610 - 5.506 =» 3.104 g AND amount of $\ce{H2O}$: «3.104/18.02 =» 0.172 mol ✔

(ii) ruled straight line passing through or close to most of the points, leaving out the two outliers «students 4 and 8» ✔

line extrapolated so that it passes through the origin ✔

(iii) Independent variable: amount «in mol» of $\ce{CuSO4}$ «or mass of hydrated salt» AND Dependent variable: amount «in mol» of $\ce{H2O}$ ✔

(iv) point for student 4 (0.032, 0.127) circled ✔

Reason: amount of $\ce{CuSO4}$ too high OR amount of $\ce{H2O}$

OR

point for student 8 (0.055, 0.332) circled ✔

Reason: amount of $\ce{CuSO4}$ too low OR amount of $\ce{H2O}$

(v) «X = gradient = $\dfrac{0.400}{0.080}$ =» 5 ✔

(i) [1] for both values to the correct number of figures (three decimal places for the loss, three significant figures for the amount). (ii) M1: line through or close to most of the points and clearly not through the two outliers; M2: line passes through the origin (within half a small division on either axis); award [1 max] for a line obviously not drawn with a ruler. (iii) [1] for both variables; accept mass before heating and mass after heating as the independent and dependent variables. (iv) M1: one of the two anomalous points identified (award M1 even if both are circled; apply the list principle if other points are circled); M2: a reason stating which amount is too high or too low, or its cause (incomplete dehydration, loss of solid); 'it lies far from the line' alone does not score. (v) [1] for X = 5; non-integer values do not score.