NECO Chemistry · Matter, atoms and chemical combination
Stoichiometry and chemical reactions: NECO Chemistry Past Questions and Answers
What the WAEC syllabus covers in Stoichiometry and chemical reactions
Our summary: Chemical symbols, formulae and equations, the laws of chemical combination, the mole, and calculations with solutions.
- Symbols, formulae and equations (Symbols of the first thirty elements and other common elements that are not among the first thirty elements.)
- Chemical symbols
- Empirical and molecular formulae (Calculations involving formulae and equations will be required. Mass and volume relationships in chemical reactions and the stoichiometry of such reactions such as: calculation of percentage composition of element.)
- Chemical equations and IUPAC names of chemical compounds ((1) Combustion reactions (including combustion of simple hydrocarbons). (2) Synthesis. (3) Displacement or replacement. (4) Decomposition. (5) Ionic reactions.)
- Laws of chemical combination ((1) Laws of conservation of mass. (2) Law of constant composition. (3) Law of multiple proportions. Explanation of the laws to balance given equations. (4) Experimental illustration of the law of conservation of mass.)
- Amount of substance ((1) Mass and volume measurements. (2) The mole as a unit of measurement; Avogadro's constant, L = 6.02 × 10²³ entities mol⁻¹. (3) Molar quantities and their uses. (4) Moles of electrons, atoms, molecules, formula units etc.)
- Mole ratios (Use of mole ratios in determining stoichiometry of chemical reactions. Simple calculations to determine the number of entities, amount of substance, mass, concentration, volume and percentage yield of product.)
- Solutions ((1) Concept of a solution as made up of solvent and solute. (2) Distinguishing between dilute solution and concentrated solution. (3) Basic, acidic and neutral solutions.)
- Concentration terms (Mass (g) or moles (mol) per unit volume. Emphasis on current IUPAC chemical terminology, symbols and conventions. Concentration be expressed as mass concentration, g dm⁻³, molar concentration, mol dm⁻³.)
- Standard solutions ((1) Preparation of some primary standards e.g. anhydrous Na₂CO₃, (COOH)₂·2H₂O/H₂C₂O₄·2H₂O. (2) Meaning of the terms primary standard, secondary standard and standard solution.)
- Preparation of solutions from liquid solutes by the method of dilution (Dilution factor.)
Syllabus content © The West African Examinations Council (WASSCE (harmonised West African syllabus)). NECO questions are matched to the WAEC syllabus topic.
NECO Chemistry questions on Stoichiometry and chemical reactions
- NECO 2009What volume of carbon (IV) oxide in dm 3 is produced at s.t.p. when 2.50g of CaCO3 reacts with excess acid according to the following equation? CaCO3(s) +…
- NECO 2009Which of the following equations is NOT balanced?
- NECO 2009C 6 H 12 O 6 What is the molar mass of the compound above? [ H=1, C=12, O=16
- NECO 2008An element Z has a combining power of 3. Which of the following formulae is correct of its compound?
- NECO 2008Matter is neither created nor destroyed in the course of any chemical reactions is a statement of the law of
- NECO 2008A solution is prepared by dissolving I .96g of H2SO4 in 250 cm3 of its solution. What is the concentration in moles per dm3?
- NECO 2003The number of hydrogen ions in 1.0dm ^3 of a 0.25 mole tetraoxosulphate(Vl) acid solution is [Avogadro constant = 6.02 x 10 ^ 23 ]
- NECO 2003What is the number of moles of NaHCO3in 250cm3 of its solution if the solution contains 8.4 g of NaHCO3 in 1 dm3 of the solution. [Na = 23, 0 = 16, C = 12, H =…
- NECO 2003What is the concentration (mol dm ^ -3 ) of a solution containing 28 g of potassium hydroxide per 100 cm ^3 of solution? (K=39; H=1; O=16)
- NECO 2003An organic compound gave the following results on analysis: C = 29.3% ; H = 5.7%; Br = 65%. What is the empirical formula of the compound? [C = 12, H = 1…
- NECO 2001if an element X with atomic number 13 combines with an element Y whose atomic number is 8 the most likely formula of the compound formed between X and Y is?
- NECO 2001in any chemical reaction, the total mass of products is always equal to that of the reactants. This Is statement of the law of:
- NECO 2001How much sodium hydroxide is required to make 250 cm3 of 0.1 molar solution? Na=23; 0=16; H=1]
- NECO 2001Which element contains the greatest number of moles?
- NECO 200120 cm3 of 0.09 mol dm3 solution of tetraoxosuiphate (Vi) acid requires 30cm3 of sodium hydroxide solution for complete neutralization. The molar concentration…
Years with Stoichiometry and chemical reactions questions in DeeepSolve's question bank
From the past questions DeeepSolve holds, not a count of everything the exam body has set.
- 2009
- 2008
- 2003
- 2001