Chemical energetics — IGCSE Chemistry (0971) questions by topic
Chemical energetics questions cover reaction pathways and enthalpy: comparing sodium hydrogencarbonate reacting with hydrochloric acid against ethanoic acid, identifying the reaction type and pathway diagram for a hydrated copper salt heating up when its anhydrous form takes on moisture, judging statements about temperature changes in endothermic and exothermic reactions, and calculating the enthalpy change for forming methane from given bond energy. Identify, plan, complete, calculate and state cover both diagram-matching and numerical energy calculations.
8 questions from 2025 papers make up this set, worth between 1 and 7 marks. Because enthalpy calculations depend on correctly signed bond-energy values, submitting your working for instant marking catches a sign error, such as treating an exothermic change as positive, before it produces a plausible-looking but wrong final answer.
May–June 2025, Paper 11
Three statements about energy changes in chemical reactions are listed. 1 In an endothermic reaction, the temperature of the surroundings increases. 2 In an exothermic reaction,…
Answer this question and get it marked →May–June 2025, Paper 12
Which reaction pathway diagram shows the largest increase in the temperature of the surroundings? (The scale on the y-axis is the same in each diagram.) A an endothermic profile…
Answer this question and get it marked →May–June 2025, Paper 21
Water is added to anhydrous copper(II) sulfate in a test-tube. The mixture becomes hot. Which type of reaction and reaction pathway diagram apply to this reaction? Each option…
Answer this question and get it marked →May–June 2025, Paper 22
A reaction pathway diagram is shown. The energy of the products is higher than the energy of the reactants, with an energy barrier (activation energy) between them. Which row…
Answer this question and get it marked →The average bond energy for the C-H bond is 413 kJ/mol. What is the enthalpy change when 1.0 mol of methane molecules is formed from carbon and hydrogen atoms? A -1652 kJ B -413…
Answer this question and get it marked →May–June 2025, Paper 31
This question is about energy changes in reactions. Table 7.1 shows the results of four experiments. Table 7.1 experiment initial temperature / degrees C final temperature /…
Answer this question and get it marked →May–June 2025, Paper 51
Solid sodium hydrogencarbonate, NaHCO3, reacts with dilute hydrochloric acid and with dilute ethanoic acid. NaHCO3(s) + HCl(aq) - NaCl(aq) + CO2(g) + H2O(l) NaHCO3(s) +…
Answer this question and get it marked →May–June 2025, Paper 61
Solid sodium hydrogencarbonate, NaHCO3, reacts with dilute hydrochloric acid and with dilute ethanoic acid. NaHCO3(s) + HCl(aq) - NaCl(aq) + CO2(g) + H2O(l) NaHCO3(s) +…
Answer this question and get it marked →Other IGCSE Chemistry topics
- Organic chemistry (31)
- The Periodic Table (29)
- Metals (23)
- Experimental techniques and chemical analysis (19)
- Chemical reactions (14)
- Acids, bases and salts (14)
- Chemical bonding (11)
- Stoichiometry (11)
- Chemistry of the environment (10)
- States of matter (9)
- Electrochemistry (9)
- Atoms, elements and compounds (8)