Physical and Chemical Changes of Matter Quiz
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Questions and Answers

What happens when milk is left at room temperature during summers?

  • It evaporates completely leaving behind a white residue
  • It becomes thicker and creamier
  • It curdles due to the action of bacteria and enzymes (correct)
  • It turns into a solid block of cheese

    • What happens when food is cooked?

  • It undergoes a chemical change only
  • It remains unchanged
  • It may undergo both physical and chemical changes (correct)
  • It undergoes a physical change only

    • What happens when grapes get fermented?

  • They become juicier
  • They become more sour in taste
  • They release carbon dioxide and ethanol (correct)
  • They turn into raisins

    • What happens when food gets digested in our body?

    <p>It may undergo both physical and chemical changes</p> Signup and view all the answers

    What do we observe when a magnesium ribbon is burnt and the ash is collected in a watch-glass?

    <p>The ash is white and powdery</p> Signup and view all the answers

    What do we observe when an iron tawa/pan/nail is left exposed to humid atmosphere?

    <p>It forms a layer of rust on its surface</p> Signup and view all the answers

    Which of the following is NOT an observation that helps determine whether a chemical reaction has taken place?

    <p>Change in pressure</p> Signup and view all the answers

    What is the product of the reaction between lead nitrate solution and potassium iodide solution?

    <p>Lead iodide</p> Signup and view all the answers

    What substances are considered the reactants in the reaction described by the word-equation: Magnesium + Oxygen → Magnesium oxide?

    <p>Magnesium and Oxygen</p> Signup and view all the answers

    What is the purpose of using chemical formulae in place of words in a chemical equation?

    <p>To make the equation more concise and useful</p> Signup and view all the answers

    What does the evolution of a gas indicate in a chemical reaction?

    <p>Formation of a new substance</p> Signup and view all the answers

    What is the symbolic representation for the reaction between magnesium and oxygen?

    <p>$Mg + O_2 → MgO$</p> Signup and view all the answers

    What is the product of burning magnesium ribbon in oxygen?

    <p>$MgO$</p> Signup and view all the answers

    What happens to magnesium ribbon when it burns in oxygen?

    <p>It changes into magnesium oxide powder</p> Signup and view all the answers

    What is the purpose of using chemical equations?

    <p>To simplify the representation of chemical reactions</p> Signup and view all the answers

    What is the purpose of burning a magnesium ribbon and collecting the ash in a watch-glass?

    <p>To observe and identify the chemical changes that occur when magnesium undergoes a chemical reaction with oxygen.</p> Signup and view all the answers

    What does the observation of burning magnesium ribbon in air and collecting the ash in a watch-glass demonstrate?

    <p>It demonstrates the occurrence of a chemical reaction.</p> Signup and view all the answers

    Why is it important to keep the burning magnesium ribbon away from the eyes during the activity?

    <p>To ensure safety and prevent any potential harm to the eyes from the intense light produced during the burning process.</p> Signup and view all the answers

    What does the observation of milk left at room temperature during summers demonstrate?

    <p>It demonstrates the spoilage of milk due to bacterial action, leading to a chemical change.</p> Signup and view all the answers

    What is the significance of observing the iron tawa/pan/nail left exposed to humid atmosphere?

    <p>It demonstrates the formation of rust through a chemical reaction with oxygen and moisture in the air.</p> Signup and view all the answers

    Why is it important to understand the indicators of chemical reactions in daily life?

    <p>To recognize and comprehend the fundamental chemical processes that occur in various everyday scenarios, leading to a better understanding of the world around us.</p> Signup and view all the answers

    What are the three observations that help us determine whether a chemical reaction has taken place?

    <p>Change in state, change in color, evolution of a gas</p> Signup and view all the answers

    What are the reactants and product in the reaction described by the word-equation: Magnesium + Oxygen → Magnesium oxide?

    <p>Magnesium and Oxygen (reactants), Magnesium oxide (product)</p> Signup and view all the answers

    What is the purpose of using chemical formulae in place of words in a chemical equation?

    <p>To represent a chemical reaction more concisely and usefully</p> Signup and view all the answers

    What is the product of burning magnesium ribbon in oxygen?

    <p>Magnesium oxide</p> Signup and view all the answers

    What does the evolution of a gas indicate in a chemical reaction?

    <p>That a chemical reaction may have taken place</p> Signup and view all the answers

    What happens when a few zinc granules are added to dilute hydrochloric acid or sulphuric acid?

    <p>Evolution of a gas is observed</p> Signup and view all the answers

    What do you observe when lead nitrate solution is added to potassium iodide solution?

    <p>Formation of a precipitate</p> Signup and view all the answers

    How can a chemical equation be made more concise and useful?

    <p>By using chemical formulae instead of words</p> Signup and view all the answers

    What is the symbolic representation for the reaction between magnesium and oxygen?

    <p>Magnesium + Oxygen → Magnesium oxide</p> Signup and view all the answers

    What do you observe when a magnesium ribbon is burnt in oxygen?

    <p>Dazzling white flame and the formation of magnesium oxide</p> Signup and view all the answers

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