An investigator researched the displacement reactions between different metals and nickel(II) sulfate solution.
The investigator added equal masses of three finely powdered metals to separate 75 cm3 samples of 0.5 mol dm-3 nickel(II) sulfate solution in a well-insulated calorimeter. They recorded the starting temperature and measured the maximum temperature change after adding each metal.
Table 1 shows the results:
| Metal | Maximum temperature change (∘C^{\circ}\text{C}∘C) |
|---|---|
| Iron | +6.2 |
| Silver | 0.0 |
| Manganese | +18.5 |
Identify the independent variable and the dependent variable in this investigation.
Write the three metals in order of decreasing reactivity (from most reactive to least reactive).
The reaction profile for the reaction between manganese and nickel(II) sulfate solution is shown below.
Which letter represents the activation energy, and which letter represents the products?