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Everyday Chemistry

General Science · Chemistry

Useful for: Railway RRB, OSSC RHT — Regular High School Teacher, OSEPA Upper Primary — Science, OSSC Science, OSSSC Govt TGT Science — CBZ, OSSSC Govt TGT Science — PCM, SSB Lecturer (Degree Colleges), SSB TGT CBZ

and 1 more exams

SSB TGT PCM

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Overview

Everyday chemistry links chemical ideas to fuels, cleaning agents, fertilisers and construction materials.

Key points

LPG is mainly butane (with propane); CNG is mainly methane.
Soaps do not lather well in hard water; detergents do.
Hard water contains calcium and magnesium salts.
Urea is a nitrogen fertiliser (about 46% N).
Chlorine is used to disinfect drinking water.

Explanation

Cement is made from limestone and clay; glass from sand (silica).
Biogas is mainly methane.
Ozone protects from UV; CFCs deplete it.
Activated charcoal is used for adsorption in filters.

Step by step

Identify the concept or law involved.
Recall the definition, unit or formula.
Check units and the direction of the effect before choosing.

Examples

The main component of LPG → butane.
The main component of CNG → methane.
Urea is used as a nitrogen fertiliser.

Traps and advanced points

Trap: Mixing LPG and CNG components.
Trap: Thinking soaps work well in hard water.
Trap: Calling urea a phosphate fertiliser.

Quick revision

LPG butane; CNG methane.
Hard water: Ca and Mg.
Urea: nitrogen.

Practice MCQs

Static-GK drill: A convex lens is commonly used to correct which defect?
1. Astigmatism only
2. Night blindness
3. Hypermetropia
4. Myopia
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Answer: (c) Hypermetropia. A convex lens is commonly used to correct Hypermetropia.
Static-GK drill: Gas exchange in human lungs occurs mainly in what structures?
1. Alveoli
2. Tendons
3. Villi
4. Nephrons
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Answer: (a) Alveoli. Gas exchange in human lungs occurs mainly in what structures? — Alveoli.
Static-GK drill: Photosynthesis in plant cells occurs mainly in which organelle?
1. Chloroplast
2. Centriole
3. Lysosome
4. Ribosome
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Answer: (a) Chloroplast. Photosynthesis in plant cells occurs mainly in Chloroplast.
Static-GK drill: The modern periodic table has how many groups?
1. 8
2. 7
3. 18
4. 16
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Answer: (c) 18. The modern periodic table has how many groups? — 18.
Static-GK drill: What is the SI unit of force?
1. joule
2. newton
3. watt
4. pascal
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Answer: (b) newton. Newton is the SI unit of force.
Which option correctly answers this General Science check: a catalyst primarily changes the?
1. rate of reaction
2. mitochondria
3. H₂O
4. iron
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Answer: (a) rate of reaction. A catalyst lowers activation-energy pathway and is regenerated overall.
LPG is mainly —
1. methane
2. butane (with propane)
3. hydrogen
4. ethanol
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Answer: (b) butane (with propane). Butane and propane.
CNG is mainly —
1. butane
2. methane
3. propane
4. oxygen
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Answer: (b) methane. Compressed natural gas = methane.
Hard water contains salts of —
1. iron and copper
2. lead only
3. sodium and potassium
4. calcium and magnesium
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Answer: (d) calcium and magnesium. Ca and Mg salts.
In hard water, which lathers well?
1. both equally
2. neither
3. soap
4. detergent
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Answer: (d) detergent. Detergents work in hard water.