Air and Atmosphere
ICSE · Class 7 · Chemistry
Flashcards for Air and Atmosphere — ICSE Class 7 Chemistry. Quick Q&A cards covering key concepts, definitions, and formulas.
Interactive on Super Tutor
Studying Air and Atmosphere? Get the full interactive chapter.
Quizzes, flashcards, AI doubt-solver and a step-by-step study plan — built for flashcards and more.
1,000+ Class 7 students started this chapter today
What is air?
Answer
Air is a mixture of gases, not a compound. It contains nitrogen, oxygen, carbon dioxide, water vapour, inert gases, and small impurities like dust and smoke.
Why is air considered a mixture and not a compound?
Answer
Air has no fixed composition, the gases keep their own properties, liquid air has no definite boiling point, and the gases can be separated by physical methods.
What are the main gases in air by volume?
Answer
Nitrogen is about 78% and oxygen is about 21% by volume. The ratio of nitrogen to oxygen is 4:1 by volume.
Why did the candle in a closed jar go out after some time?
Answer
The candle used up the oxygen in the jar. Oxygen supports burning, so when the oxygen got finished, the flame went out.
What happened to the mercury level in Lavoisier’s bell jar experiment?
Answer
The mercury level rose by 1/5th of the total volume of the bell jar. This showed that 1/5th of air is active gas, oxygen.
Write the balanced equation for the mercury oxidation reaction in Lavoisier’s experiment.
Answer
2Hg + O2 --heat--> 2HgO. Mercury combines with oxygen on heating to form mercury(II) oxide.
Write the balanced equation for mercury oxide decomposition.
Answer
2HgO --heat--> 2Hg + O2. On heating, mercury(II) oxide breaks down to give mercury and oxygen.
Who first discovered oxygen, and how was it obtained?
Answer
Joseph Priestley first discovered oxygen in 1774 by heating mercury(II) oxide. He named it active air.
+40 more flashcards available
Practice AllFrequently Asked Questions
What are the important topics in Air and Atmosphere for ICSE Class 7 Chemistry?
How to score full marks in Air and Atmosphere — ICSE Class 7 Chemistry?
How many flashcards are available for Air and Atmosphere?
Sources & Official References
Content is aligned to the official syllabus. Refer to the board website for the latest curriculum.
More resources for Air and Atmosphere
Practice Quiz
Test yourself with a quick quiz
Important Questions
Practice with board exam-style questions
Revision Notes
Key points for last-minute revision
Formula Sheet
All formulas in one place
Chapter Summary
Understand the chapter at a glance
Concept Maps
See how topics connect visually
Study Plan
Step-by-step plan to ace this chapter
Syllabus
What topics to cover
NCERT Solutions
Every textbook question solved step by step
For serious students
Get the full Air and Atmosphere chapter — for free.
Quizzes, flashcards, AI doubt-solver and a step-by-step study plan for ICSE Class 7 Chemistry.