Sodium hydrogencarbonate reacts with citric acid solution in an endothermic reaction.
The equation for the reaction is: C6H8O7(aq)+3NaHCO3(s)→Na3C6H5O7(aq)+3H2O(l)+3CO2(g)\text{C}_6\text{H}_8\text{O}_7(\text{aq}) + 3\text{NaHCO}_3(\text{s}) \rightarrow \text{Na}_3\text{C}_6\text{H}_5\text{O}_7(\text{aq}) + 3\text{H}_2\text{O}(\text{l}) + 3\text{CO}_2(\text{g})C6H8O7(aq)+3NaHCO3(s)→Na3C6H5O7(aq)+3H2O(l)+3CO2(g)
A student investigated the effect of changing the mass of sodium hydrogencarbonate on the lowest temperature reached by the reaction mixture.
Determine the gradient of the line of best fit in Figure 1. Use the equation: Gradient=Change in lowest temperatureChange in mass\text{Gradient} = \frac{\text{Change in lowest temperature}}{\text{Change in mass}}Gradient=Change in massChange in lowest 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.