Equations
14 review questions with answers for Equations. Read them here, or play the set as a class game on the projector. Free to host, and students join with a code.
Substances present at the start of a reaction?
- Products
- Catalysts
- ReactantsRight answer
- Solvents
What this set covers
Reading and balancing chemical equations, from reactants and state symbols to coefficients and counting atoms. Reaction types such as displacement, thermal decomposition and combustion appear, along with precipitates and the ionic equation for acid-base reactions.
- Common mix-up
- Students often change subscripts instead of coefficients when balancing: in 3H₂O the 3 multiplies the whole formula, giving 6 hydrogen atoms, while a subscript would change the substance itself.
- Review tip
- Balance Mg + HCl and N₂ + H₂ by listing atom counts on each side first, then tick them off, and finally add state symbols.
All 14 questions and answers
Substances present at the start of a reaction?
Answer: Reactants
Law explaining why a balanced equation has the same atoms on each side?
Answer: Conservation of mass
State symbol for a gas?
Answer: (g)
Coefficient of H₂ when N₂ + H₂ → NH₃ is balanced?
Answer: 3
Coefficient of HCl when Mg + HCl → MgCl₂ + H₂ is balanced?
Answer: 2
Total number of atoms in one formula unit of CaCO₃?
Answer: 5
Number of hydrogen atoms shown by 3H₂O?
Answer: 6
Word equation: magnesium + oxygen → …?
Answer: Magnesium oxide
Reaction in which a more reactive metal takes the place of a less reactive one?
Answer: Displacement
Breaking down a compound by heating it?
Answer: Thermal decomposition
Reaction of a fuel with oxygen that releases heat and light?
Answer: Combustion
Gain of oxygen by a substance?
Answer: Oxidation
Insoluble solid formed when two solutions are mixed?
Answer: Precipitate
Ionic equation for neutralisation?
Answer: H⁺ + OH⁻ → H₂O
Play it as a class game
Play this set opens it in splycr, where you can host it for your class straight away. Hosting needs no account: put the room code on the projector, and students join from a phone with the code and their first name. Each question plays as multiple choice, and the three wrong options were written for that question.