Question 1
Paper 2Medium3 marksCitric acid solution is mixed with solid sodium hydrogencarbonate in an insulated cup. Treat the reacting chemicals as the system and the solution and cup as the surroundings. Figure 1 shows the measured temperature of the solution before and after mixing; the reagents are mixed immediately after the reading at
(a)[1]
Determine the temperature change of the surroundings from immediately before mixing to the lowest recorded value. Include the sign.
(b)[2]
Hence classify the reaction and explain the temperature change, referring to energy transfer, particle kinetic energy and conservation of energy.