12 Questions
What form of energy is causing the decomposition reactions in black and white photography?
Light energy
Why is the amount of gas collected in one of the test tubes in Activity 1.7 double that of the other? Name this gas.
The gas collected is hydrogen. The amount is double due to the decomposition of water into hydrogen and oxygen gas during the electrolysis process.
Name the substance used for white washing and write its formula. Also, provide the reaction of this substance with water.
The substance used for white washing is slaked lime with the formula Ca(OH)2. The reaction of slaked lime with water is: Ca(OH)2 + H2O -> Ca(OH)2
Give two examples of oxidation with gain of oxygen.
- Rusting of iron: Fe + O2 -> Fe2O3
- Combustion of methane: CH4 + 2O2 -> CO2 + 2H2O
Give two examples of reduction with loss of oxygen.
- Reduction of copper oxide: CuO + H2 -> Cu + H2O
- Reduction of iron oxide: Fe2O3 + 3CO -> 2Fe + 3CO2
Why do we apply paint on iron articles?
We apply paint on iron articles to prevent them from rusting by preventing exposure to air and moisture.
Why are oil and fat containing food items flushed with nitrogen?
Oil and fat containing food items are flushed with nitrogen to prevent them from becoming rancid by reducing exposure to oxygen.
Give one example of corrosion and one example of rancidity.
Corrosion example: Rusting of iron Rancidity example: Spoilage of cooking oil
What is the purpose of Activity 1.1 in the text?
To observe a chemical reaction by burning a magnesium ribbon
Why is it important to clean the magnesium ribbon before burning it in Activity 1.1?
To remove any impurities or coatings that might interfere with the observation of the chemical reaction
What caution is provided before performing Activity 1.1?
The activity requires the teacher's assistance and students should wear eye protection
What is the significance of observing the magnesium ribbon burning in Activity 1.1?
To demonstrate the occurrence of a chemical reaction and observe the formation of ash
This quiz covers topics related to gain or loss of oxygen, oxidation, reduction, corrosion, rancidity, and practical applications like applying paint on iron articles and flushing oil and fat containing food items with nitrogen. It includes examples for each concept to enhance the understanding.
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