Chemical Equation MCQs Quiz | Class 10
This quiz covers Class X Science (Code 086), Unit I: Chemical Substances – Nature and Behaviour, focusing on the topic of Chemical Equations. The questions test your understanding of writing equations at both word and symbolic levels, balancing chemical reactions, and identifying physical states. Complete the quiz to assess your knowledge, view your detailed score, and download the full answer key as a PDF for revision.
Overview of Chemical Equations
A chemical equation is the symbolic representation of a chemical reaction. It uses formulae and symbols to describe the reactants (substances taking part in the reaction) and products (substances formed). In Class 10 Science, Unit I, mastering the skill of writing and balancing these equations is fundamental.
Key Concepts
- Word Equation: Represents reactions using the names of substances (e.g., Magnesium + Oxygen -> Magnesium Oxide).
- Skeletal Equation: Uses chemical formulae but is not balanced for mass (e.g., Mg + O2 -> MgO).
- Balanced Equation: Has an equal number of atoms of each element on both reactants and products sides, obeying the Law of Conservation of Mass.
Writing Symbols of Physical States
To make an equation more informative, the physical states of reactants and products are mentioned along with their chemical formulae.
| State | Symbol | Description |
|---|---|---|
| Solid | (s) | Substance is in solid form or a precipitate. |
| Liquid | (l) | Substance is in liquid form (e.g., water). |
| Gas | (g) | Substance is in gaseous form or evolved as gas. |
| Aqueous | (aq) | Substance is dissolved in water. |
Quick Revision Points
- Reactants are written on the left-hand side (LHS) with a plus (+) sign between them.
- Products are written on the right-hand side (RHS) with a plus (+) sign between them.
- The arrow points towards the products and shows the direction of the reaction.
- Conditions like temperature, pressure, or catalyst are written above or below the arrow.
Extra Practice Questions
- Write the balanced equation for: Hydrogen + Chlorine -> Hydrogen Chloride.
- What does the symbol (aq) signify in a reaction?
- Why should a skeletal chemical equation be balanced?
- Translate to a chemical equation: Zinc reacts with Silver Nitrate to produce Zinc Nitrate and Silver.
- Identify the reactants in: C + O2 -> CO2.
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