Magnesium reacts with dilute hydrochloric acid in an exothermic reaction.
The equation for the reaction is: Mg(s)+2HCl(aq)→MgCl2(aq)+H2(g)\text{Mg(s)} + 2\text{HCl(aq)} \rightarrow \text{MgCl}_2(\text{aq}) + \text{H}_2(\text{g})Mg(s)+2HCl(aq)→MgCl2(aq)+H2(g)
A student investigated the effect of changing the mass of magnesium ribbon on the highest temperature reached by the reaction mixture.
Determine the gradient of the line of best fit in Figure 1. Use the equation: Gradient=Change in highest temperatureChange in mass\text{Gradient} = \frac{\text{Change in highest temperature}}{\text{Change in mass}}Gradient=Change in massChange in highest temperature Give the unit.
The initial temperature of the reaction mixture is where the line of best fit would meet the yyy-axis. Determine the initial temperature of the reaction mixture by extrapolating the line of best fit to a mass of 0.0 g0.0\text{ g}0.0 g.
Exothermic and endothermic reactions Questions
Practise AQA GCSE Chemistry Exothermic and endothermic reactions with exam-style questions for Foundation and Higher tier. 24 questions covering Energy transfer during exothermic and endothermic reactions, Reaction profiles, and The energy change of reactions (HT only), matched to the AQA GCSE Chemistry (8462) specification and written in Paper 1 and Paper 2 style. Every question includes a full worked solution and mark scheme, so you can see where marks are awarded rather than just whether you got the answer right.