Chemical Reactions(General Knowledge > General Science ) Questions and Answers

Question 1. What type of reaction is illustrated below?FeS + Hal --> H2S + FeCl
  1.    synthesis
  2.    decomposition
  3.    single replacement
  4.    double replacement
Explanation:-
Answer: Option D. -> double replacement
Question 2. Provides evidence that a chemical reaction has occurred
  1.    dissolving 
  2.    melting
  3.    formation of a gas
  4.    bending
Explanation:-
Answer: Option C. -> formation of a gas
Question 3. Which type of reaction takes place in the presence of oxygen and produces carbon dioxide and water?
  1.    double replacement 
  2.    decomposition 
  3.    combustion 
  4.    single replacement
Explanation:-
Answer: Option C. -> combustion 
Question 4. Describes the number of molecules in a compound and is used to balance a chemical reaction
  1.    coefficient 
  2.    subscript
  3.    superscript
  4.    SI unit
Explanation:-
Answer: Option A. -> coefficient 
Question 5. What is the probable product of a double-replacement reaction?
  1.    A new compound and a replaced metal
  2.    A new compound and a replaced nonmetal
  3.    2 different compounds 1 aqueous and 1 that is a solid, liquid or gas
  4.    A single compound
Explanation:-
Answer: Option C. -> 2 different compounds 1 aqueous and 1 that is a solid, liquid or gas
Question 6. Which of the following is NOT a sign of a chemical reaction?
  1.    Color changes
  2.    Cutting into fourths
  3.    Light is produced
  4.    Gas is formed
Explanation:-
Answer: Option B. -> Cutting into fourths
Question 7. Potassium iodide is a catalyst in a chemical reaction where would this be placed when writing the chemical reaction?
  1.    product side
  2.    reactant side
  3.    above the arrow
  4.    left out 
Explanation:-
Answer: Option C. -> above the arrow
Question 8. A chemical reaction that absorbs heat
  1.    Single replacement
  2.    Exothermic
  3.    Endothermic
  4.    Decomposition
Explanation:-
Answer: Option C. -> Endothermic
Question 9. What does the Law of Conservation of Mass state?
  1.    Matter cannot be gained or lost in a chemical reaction.
  2.    Matter can only be lost in a chemical reaction.
  3.    Matter can only be gained in a chemical reaction.
  4.    Matter can be gained and lost in a chemical reaction. 
Explanation:-
Answer: Option A. -> Matter cannot be gained or lost in a chemical reaction.
Question 10. True or False: In a complete chemical equation, there must be the same number of atoms of each element on the reactants and products side
  1.    True
  2.    False
Explanation:-
Answer: Option A. -> True
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