1. Stoichiometry is the branch of chemistry dealing with quantitative calculations in chemical reactions.
2. It is also known as chemical arithmetic.
3. All stoichiometric calculations are based on balanced chemical equations.
4. Coefficients of a balanced equation represent mole ratios.
5. Mole is the SI unit of amount of substance.
6. One mole of any substance contains 6.022 × 10p²³ particles.
7. This number is called Avogadro’s number.
8. Particles may be atoms, molecules, ions, or formula units.
9. Molar mass is the mass of one mole of a substance and is expressed in g/mol.
10. Atomic mass in a.m.u is numerically equal to molar mass in grams.
11. Mole concept connects mass, number of particles, and volume.
12. Mass–mole conversions are done using molar mass.
13. For gases, mole is related to volume at STP.
14. At STP, 1 mole of any gas occupies 22.4 dm³.
15. Rounding off is used to keep numerical results accurate.
16. If the next digit is 5 or more, round up; if less than 5, round down.
17. Scientific (exponential) notation is used for very large or very small numbers.
18. Numbers are written in the form N × 10ⁿ.
19. Scientific notation simplifies calculations and improves accuracy.
20. Limiting reactant is the reactant that is consumed first in a reaction.
21. It determines the maximum amount of product formed.
22. The reactant present in extra amount is called excess reactant.
23. To find the limiting reactant, all reactants are converted into moles.
24. Theoretical yield is the maximum amount of product calculated from the equation.
25. Practical (actual) yield is the amount of product obtained experimentally.
26. Loss of yield occurs due to side reactions and experimental errors.
27. Percentage yield shows the efficiency of a chemical reaction.
28. Knowing stoichiometry is important in labs, factories, making fertilizers, medicines, fuels, and even in environmental processes