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  1. Problems
  2. /IB

IB problems

495 problems for IB practice, each with a worked solution. Try each one on paper first, then check your answer.

Other examsJEE MainJEE AdvancedNEETBITSATWBJEEBoard ExamOlympiadSATAPA-LevelGaokaoPCEP (Python Institute)PCAP (Python Institute)

Choose a topic to see its subtopics.

73 problems
Type:
1.
Benzene melts at 278.7 K, and its enthalpy of fusion is 9.87 kJ/mol. New
High School (11–12) · Entropy, Gibbs Energy and SpontaneityBoard Exam, A-Level, IBStemPy LabStemPy Lab
Easy
2.
Predict the sign of Δ S for each change, and give the reason. New
High School (11–12) · Entropy, Gibbs Energy and SpontaneityBoard Exam, AP, A-Level, IBStemPy LabStemPy Lab
Easy
3.
Sulphur trioxide is made by 2SO₂(g) + O₂(g) → 2SO₃(g). New
High School (11–12) · Entropy, Gibbs Energy and SpontaneityBoard Exam, AP, A-Level, IBStemPy LabStemPy Lab
Medium
4.
For N₂(g) + 3H₂(g) → 2NH₃(g), Δ H° = -92.4 kJ/mol and Δ S° = -198.7 J/(K mol). New
High School (11–12) · Entropy, Gibbs Energy and SpontaneityBoard Exam, AP, A-Level, IBStemPy LabStemPy Lab
Medium
5.
Magnesium carbonate decomposes: MgCO₃(s) → MgO(s) + CO₂(g), with Δ H° = +117.6 kJ/mol and Δ S° =… New
High School (11–12) · Entropy, Gibbs Energy and SpontaneityBoard Exam, AP, A-Level, IBStemPy LabStemPy Lab
Medium
6.
Four reactions have these signs. (a) Δ H < 0, Δ S > 0. New
High School (11–12) · Entropy, Gibbs Energy and SpontaneityBoard Exam, AP, A-Level, IBStemPy LabStemPy Lab
Easy
7.
At 298 K a reaction has Δ G° = -17.1 kJ/mol. New
High School (11–12) · Entropy, Gibbs Energy and SpontaneityBoard Exam, AP, A-Level, IBStemPy LabStemPy Lab
Medium
8.
A reaction has K = 2.5 × 10⁻³ at 500 K. Find Δ G° at this temperature. New
High School (11–12) · Entropy, Gibbs Energy and SpontaneityBoard Exam, AP, A-Level, IBStemPy LabStemPy Lab
Medium
9.
For N₂O₄(g) ⇌ 2NO₂(g), Δ H° = +57.2 kJ/mol and Δ S° = +175.8 J/(K mol). New
High School (11–12) · Entropy, Gibbs Energy and SpontaneityJEE Main, NEET, BITSAT, WBJEE, Board Exam, AP, A-Level, IBStemPy LabStemPy Lab
Hard
10.
50.0 mL of 1.00 M hydrochloric acid is mixed with 50.0 mL of 1.00 M sodium hydroxide in a… New
High School (11–12) · Enthalpy and Hess's LawBoard Exam, AP, A-Level, IBStemPy LabStemPy Lab
Easy
11.
Quicklime is made by heating limestone: CaCO₃(s) → CaO(s) + CO₂(g). New
High School (11–12) · Enthalpy and Hess's LawNEET, Board Exam, AP, A-Level, IBStemPy LabStemPy Lab
Medium
12.
How much heat turns 36.0 g of ice at 273 K into steam at 373 K? New
High School (11–12) · Enthalpy and Hess's LawNEET, Board Exam, AP, A-Level, IBStemPy LabStemPy Lab
Medium
13.
Methane cannot be made cleanly from carbon and hydrogen, so its Δf H° is found with Hess's law. New
High School (11–12) · Enthalpy and Hess's LawJEE Main, NEET, BITSAT, WBJEE, Board Exam, AP, A-Level, IB, GaokaoStemPy LabStemPy Lab
Medium
14.
Estimate Δr H for C₂H₄(g) + H₂(g) → C₂H₆(g) from the mean bond enthalpies: C=C 611, H-H 435, C-C… New
High School (11–12) · Enthalpy and Hess's LawNEET, Board Exam, AP, A-Level, IBStemPy LabStemPy Lab
Medium
15.
Breaking one mole of CH₄(g) into atoms takes 1665 kJ. New
High School (11–12) · Enthalpy and Hess's LawJEE Main, NEET, BITSAT, WBJEE, Board Exam, AP, A-Level, IB, GaokaoStemPy LabStemPy Lab
Hard
16.
Water boils at 373 K and hydrogen sulphide at 213 K, although an H₂S molecule is almost twice as… New
High School (11–12) · Molecular Orbitals and Hydrogen BondsBoard Exam, AP, A-Level, IBStemPy LabStemPy Lab
Easy
17.
Hydrogen sulphide, hydrogen selenide and hydrogen telluride boil at 213 K, 232 K and 271 K; their… New
High School (11–12) · Molecular Orbitals and Hydrogen BondsBoard Exam, AP, A-Level, IBStemPy LabStemPy Lab
Hard
18.
Silicon (4 outer electrons), phosphorus (5) and sulphur (6) each form a chloride: SiCl₄, PCl₃ and… New
High School (11–12) · Shapes of Molecules and HybridisationBoard Exam, AP, A-Level, IBStemPy LabStemPy Lab
Easy
19.
Xenon is a noble gas with 8 outer electrons, yet it forms XeF₂, XeF₄ and XeF₆. New
High School (11–12) · Shapes of Molecules and HybridisationNEET, Board Exam, AP, A-Level, IBStemPy LabStemPy Lab
Medium
20.
Predict the shapes of the ammonium ion NH₄⁺, the hydronium ion H₃O⁺ and the amide ion NH₂⁻. New
High School (11–12) · Shapes of Molecules and HybridisationBoard Exam, AP, A-Level, IBStemPy LabStemPy Lab
Medium
21.
Chlorine has 7 outer electrons. Find the electron pairs and lone pairs on chlorine in ClF₃. New
High School (11–12) · Shapes of Molecules and HybridisationBoard Exam, AP, A-Level, IBStemPy LabStemPy Lab
Hard
22.
Count the sigma and pi bonds in propene, CH₂=CH-CH₃, and in propyne, HC≡C-CH₃. New
High School (11–12) · Shapes of Molecules and HybridisationBoard Exam, AP, IBStemPy LabStemPy Lab
Medium
23.
Hydrogen chloride, chlorine and nitrogen are all covalent. New
High School (11–12) · Shapes of Molecules and HybridisationBoard Exam, AP, IBStemPy LabStemPy Lab
Medium
24.
Ethene, CH₂=CH₂, is flat. What is the hybridisation of each carbon atom? New
High School (11–12) · Shapes of Molecules and HybridisationBoard Exam, AP, IBStemPy LabStemPy Lab
Medium
25.
Count the valence electrons in the sulfate ion, SO₄²⁻. New
High School (11–12) · Lewis Structures and Ionic BondsBoard Exam, AP, IBStemPy LabStemPy Lab
Medium
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