The effect of temperature on the rate of the reaction between a sodium thiosulfate solution and a hydrochloric acid solution was investigated - Leaving Cert Chemistry - Question 3 - 2020

During each run, a color change was observed in the reaction mixture as solid sulfur precipitated out, causing the solution to turn increasingly opaque.

The flasks were monitored visually. A cross marked below the flask was used to judge clarity; the time was recorded when the cross became obscured by the precipitate.

Run 1: 0.002 Run 2: 0.005 Run 3: 0.010 Run 4: 0.018 Run 5: 0.029 Run 6: 0.062 Run 7: 0.111

For plotting the graph, the x-axis should represent the temperature in °C, while the y-axis depicts the reaction rate (r in s⁻¹). Connect the points plotted for each run with a smooth curve to demonstrate the relationship between temperature and reaction rate.

Using the graph, it appears that the rate doubles approximately for every increase of about 10 °C in temperature.

The observation that the reaction rate doubles with every increase of approximately 10 °C indicates that higher temperatures enhance particle energy and frequency of collisions, leading to more effective interactions between reactants.

Run 8's corresponding rate would likely be lower than the plotted points for temperatures up to 43 °C, but higher than those below it, assuming the flask affects the reaction's visibility.

The depth of liquid in Run 8 would be less than in the original flasks due to the different shape of the flask; a wider flask would have a lower height with the same volume, affecting the exposure of the liquid to heat.