A student investigates the energy released when hydrochloric acid completely neutralises sodium hydroxide solution - AQA - GCSE Chemistry - Question 8 - 2015 - Paper 3
Question 8
A student investigates the energy released when hydrochloric acid completely neutralises sodium hydroxide solution.
The student uses the apparatus shown in Figure 4.... show full transcript
Worked Solution & Example Answer:A student investigates the energy released when hydrochloric acid completely neutralises sodium hydroxide solution - AQA - GCSE Chemistry - Question 8 - 2015 - Paper 3
Step 1
Suggest a cause for the anomalous result when 20 cm³ of hydrochloric acid is added.
96%
114 rated
Only available for registered users.
Sign up now to view full answer, or log in if you already have an account!
Answer
Possible causes for the anomalous result could include incorrect measurement of temperature or volume, incorrect recording of temperature, failure to stir, or heat loss.
Step 2
Suggest the true value of the temperature of the anomalous point.
99%
104 rated
Only available for registered users.
Sign up now to view full answer, or log in if you already have an account!
Answer
Temperature = 32 - 33 °C
Step 3
What was the total volume of the mixture when the maximum temperature was reached?
96%
101 rated
Only available for registered users.
Sign up now to view full answer, or log in if you already have an account!
Answer
Total volume of the mixture = 55 cm³
Step 4
Calculate the overall temperature increase in this experiment.
98%
120 rated
Only available for registered users.
Sign up now to view full answer, or log in if you already have an account!
Answer
Overall temperature increase = 20 °C
Step 5
Use your answers to 8(a)(iii) and 8(a)(iv) and the equation to calculate the energy released in the reaction. Give the unit.
97%
117 rated
Only available for registered users.
Sign up now to view full answer, or log in if you already have an account!
Answer
Energy released = 4620 J (or kJ if divided by 1000)
Step 6
Explain why starting with 50 cm³ of sodium hydroxide solution would make no difference to the overall temperature increase.
97%
121 rated
Only available for registered users.
Sign up now to view full answer, or log in if you already have an account!
Answer
Starting with 50 cm³ of sodium hydroxide solution would not affect the overall temperature increase because the ratio of reactants remains the same, thereby leading to the same energy change during the reaction.
