Chemical Reactions Quiz - CBSE Class 10 Science
Free practice quiz: Chemical Reactions (CBSE Class 10 Science). 19 multiple-choice questions with answers and explanations. Play online, no sign-up needed.
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What is a chemical reaction?
- A process where substances interact to form new substances
- A phenomenon where light is emitted
- A situation where heat is absorbed
- A condition where substances split into atoms
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Answer: A. A process where substances interact to form new substances
A chemical reaction involves the transformation of one or more substances into different substances. This transformation involves bond breaking and forming, leading to new substances.
Which is an example of an exothermic reaction?
- Melting of ice
- Rusting of iron
- Combustion of wood
- Dissolution of ammonium nitrate in water
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Answer: C. Combustion of wood
Exothermic reactions release energy in the form of heat or light. Combustion of wood is an exothermic process as it releases heat and light.
In which type of reaction do two or more reactants combine to form a single product?
- Decomposition reaction
- Combination reaction
- Displacement reaction
- Redox reaction
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Answer: B. Combination reaction
A combination reaction is characterized by two or more reactants combining to form a single product, also known as a synthesis reaction.
What occurs in a double displacement reaction?
- Two elements exchange places
- One element replaces another in a compound
- Products form reactants
- Reactants combine to form a complex compound
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Answer: A. Two elements exchange places
In a double displacement reaction, the ions of two compounds exchange places in an aqueous solution to form two new compounds.
How does temperature affect the rate of a chemical reaction?
- Higher temperature always slows the reaction
- Higher temperature lowers activation energy
- Higher temperature increases molecular collisions
- Higher temperature makes reactants vibrate
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Answer: C. Higher temperature increases molecular collisions
An increase in temperature generally increases reaction rates because the number of molecular collisions with sufficient energy, or activation energy, increases.