Decomposition Reactions
Chemistry ⇒ Chemical Reactions and Equations
Decomposition Reactions starts at 9 and continues till grade 12.
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See sample questions for grade 9
A student heats a sample of potassium chlorate (KClO3) and collects a gas. What is the gas likely to be?
A white solid turns yellow on heating and releases a brown gas. The reaction is: 2Pb(NO3)2 → 2PbO + 4NO2 + O2. What is the brown gas?
Describe what happens when silver chloride is exposed to sunlight.
Explain the difference between thermal, electrolytic, and photodecomposition reactions.
A student heats a sample of potassium chlorate (KClO3) and collects a gas. What is the gas likely to be?
A student observes that a white powder turns yellow on heating and returns to white on cooling. The powder is likely to be: (1) Lead(II) nitrate (2) Zinc oxide (3) Calcium carbonate (4) Silver chloride
A white solid turns yellow on heating and releases a brown gas. The reaction is: 2Pb(NO3)2 → 2PbO + 4NO2 + O2. What is the brown gas?
Calculate the number of moles of oxygen gas produced when 0.5 moles of potassium chlorate decompose according to the equation: 2KClO3 → 2KCl + 3O2.
A student observes that a white powder turns yellow on heating and returns to white on cooling. The powder is likely to be: (1) Lead(II) nitrate (2) Zinc oxide (3) Calcium carbonate (4) Silver chloride
Which of the following best describes a decomposition reaction? (1) Two or more substances combine to form a new compound (2) A compound breaks down into two or more simpler substances (3) Two elements react to form a compound (4) An element replaces another in a compound
Which of the following compounds can be decomposed by electricity? (1) NaCl (molten) (2) CaCO3 (3) AgCl (4) KClO3
Which of the following is a characteristic of decomposition reactions? (1) They always release energy (2) They always require a catalyst (3) They involve a single reactant (4) They always produce gases
Complete the following reaction: 2Pb(NO3)2 → ________ + 4NO2 + O2
Decomposition reactions are generally ________ reactions, meaning they require energy to proceed.
Fill in the blank: The decomposition of calcium carbonate is an example of a ________ decomposition reaction.
Fill in the blank: The decomposition of hydrogen peroxide is represented by the equation 2H2O2 → 2H2O + ________.
Is the following reaction a decomposition reaction? 2KClO3 → 2KCl + 3O2
True or False: All decomposition reactions require heat to occur.
True or False: Decomposition reactions always produce only elements as products.
True or False: Decomposition reactions can be used to extract metals from their compounds.
