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A thermometer was inserted through the plastic lid of an insulated cup containing 100 cm³ of 1.0 M sodium hydroxide solution - Leaving Cert Chemistry - Question 3 - 2021
Question 3
A thermometer was inserted through the plastic lid of an insulated cup containing 100 cm³ of 1.0 M sodium hydroxide solution. A timer was started and the temperature... show full transcript
Worked Solution & Example Answer:A thermometer was inserted through the plastic lid of an insulated cup containing 100 cm³ of 1.0 M sodium hydroxide solution - Leaving Cert Chemistry - Question 3 - 2021
Step 1
Plot a graph (on graph paper) of temperature versus time (x-axis).
Answer
To plot the graph, create a coordinate system where the x-axis represents time (in minutes) and the y-axis represents temperature (in °C). Using the provided temperature data at the respective times, plot the points: (0.0, 16.0), (0.5, 16.0), (1.0, 16.0), (1.5, 16.0), (2.0, 16.0), (2.5, 22.1), (3.0, 22.6), (3.5, 22.5), (4.0, 22.3), (5.0, 22.4). Connect these points with a smooth line to show the temperature change over time.
Step 2
Step 3
Is the neutralisation of sodium hydroxide solution by hydrochloric acid exothermic or endothermic? Justify your answer.
Answer
The neutralisation of sodium hydroxide by hydrochloric acid is exothermic. This is justified by the fact that the temperature of the solution increases upon the addition of HCl to NaOH, indicating that heat is released during the reaction.
Step 4
Why is an insulated cup, like that shown above, a suitable container for this experiment?
Answer
An insulated cup is suitable because it minimizes heat loss to the surroundings, allowing for a more accurate measurement of the temperature change during the reaction. This ensures that the heat exchange between the reactants is effectively captured.
Step 5
Step 6
Describe one precaution that should have been taken when using this solution.
Answer
One precaution that should have been taken is to wear appropriate personal protective equipment (PPE), such as gloves and safety goggles, to protect against splashes or spills of the corrosive sodium hydroxide solution.
Step 7