31 Questions
What happens when milk is left at room temperature during summers?
It curdles due to the action of bacteria and enzymes
What happens when food is cooked?
It may undergo both physical and chemical changes
What happens when grapes get fermented?
They release carbon dioxide and ethanol
What happens when food gets digested in our body?
It may undergo both physical and chemical changes
What do we observe when a magnesium ribbon is burnt and the ash is collected in a watch-glass?
The ash is white and powdery
What do we observe when an iron tawa/pan/nail is left exposed to humid atmosphere?
It forms a layer of rust on its surface
Which of the following is NOT an observation that helps determine whether a chemical reaction has taken place?
Change in pressure
What is the product of the reaction between lead nitrate solution and potassium iodide solution?
Lead iodide
What substances are considered the reactants in the reaction described by the word-equation: Magnesium + Oxygen → Magnesium oxide?
Magnesium and Oxygen
What is the purpose of using chemical formulae in place of words in a chemical equation?
To make the equation more concise and useful
What does the evolution of a gas indicate in a chemical reaction?
Formation of a new substance
What is the symbolic representation for the reaction between magnesium and oxygen?
$Mg + O_2 → MgO$
What is the product of burning magnesium ribbon in oxygen?
$MgO$
What happens to magnesium ribbon when it burns in oxygen?
It changes into magnesium oxide powder
What is the purpose of using chemical equations?
To simplify the representation of chemical reactions
What is the purpose of burning a magnesium ribbon and collecting the ash in a watch-glass?
To observe and identify the chemical changes that occur when magnesium undergoes a chemical reaction with oxygen.
What does the observation of burning magnesium ribbon in air and collecting the ash in a watch-glass demonstrate?
It demonstrates the occurrence of a chemical reaction.
Why is it important to keep the burning magnesium ribbon away from the eyes during the activity?
To ensure safety and prevent any potential harm to the eyes from the intense light produced during the burning process.
What does the observation of milk left at room temperature during summers demonstrate?
It demonstrates the spoilage of milk due to bacterial action, leading to a chemical change.
What is the significance of observing the iron tawa/pan/nail left exposed to humid atmosphere?
It demonstrates the formation of rust through a chemical reaction with oxygen and moisture in the air.
Why is it important to understand the indicators of chemical reactions in daily life?
To recognize and comprehend the fundamental chemical processes that occur in various everyday scenarios, leading to a better understanding of the world around us.
What are the three observations that help us determine whether a chemical reaction has taken place?
Change in state, change in color, evolution of a gas
What are the reactants and product in the reaction described by the word-equation: Magnesium + Oxygen → Magnesium oxide?
Magnesium and Oxygen (reactants), Magnesium oxide (product)
What is the purpose of using chemical formulae in place of words in a chemical equation?
To represent a chemical reaction more concisely and usefully
What is the product of burning magnesium ribbon in oxygen?
Magnesium oxide
What does the evolution of a gas indicate in a chemical reaction?
That a chemical reaction may have taken place
What happens when a few zinc granules are added to dilute hydrochloric acid or sulphuric acid?
Evolution of a gas is observed
What do you observe when lead nitrate solution is added to potassium iodide solution?
Formation of a precipitate
How can a chemical equation be made more concise and useful?
By using chemical formulae instead of words
What is the symbolic representation for the reaction between magnesium and oxygen?
Magnesium + Oxygen → Magnesium oxide
What do you observe when a magnesium ribbon is burnt in oxygen?
Dazzling white flame and the formation of magnesium oxide
Test your knowledge about physical and chemical changes of matter with this quiz. Explore how different substances change in various situations, such as when food is cooked or when grapes get fermented.
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