SSC CGL Chemistry · Free notes

Mole Concept and Stoichiometry: SSC CGL Chemistry

Mole Concept and Stoichiometry has seven questions in the SSC CGL Tier I bank: two from the 2023 shifts and five from the 2024 shifts, and none from the 2025 shifts. Three are short sums, a percentage composition or a balanced equation; the rest ask Avogadro's number or who gave which law. One page gives the formula and the names.

The handout has every subtopic, worked example, formula and trap with answers shown. The formula sheet is the chapter’s formulas and traps alone, on one page.

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Subtopic notes

The Mole and the Laws of Combination
7 PYQs
Avogadro's number, the percentage of an element in a compound, balancing an equation, and the laws of chemical combination with the people and years behind them.

Formula & revision sheet

1 formulas · 1 reference tables · 2 gotchas across all subtopics — the exam-eve cheat-sheet

The Mole and the Laws of Combination

Formulas (1)

Percentage composition and balancing · Percentage composition $\%\ \text{element} = \frac{\text{mass of element in formula}}{\text{molar mass}} \times 100$

Reference tables (1)

The laws and their discoverers5 rows

Law or work	Who and when
Conservation of mass	Lavoisier
Method of Chemical Nomenclature	Lavoisier, 1787Q
Equal volumes, equal molecules	Avogadro, 1811Q
Definite proportions	Proust
Multiple proportions	Dalton

Watch out for (2)

Check the percentages add to 100
→ Percentage composition and balancing
Mass is Lavoisier, energy is physics
→ The laws and their discoverers

PYQ weightage by concept

2 concepts · 7 PYQs — where the marks actually sit, so you know what to drill first

The Mole and the Laws of Combination7 PYQs · 100%

Concept	PYQs	Share
Percentage composition and balancing	4	57%
The laws and their discoverers	3	43%

Test yourself on a real paper

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