From grams to moles to atoms
"From grams to moles to atoms" is a free, interactive Class 11 Chemistry simulation for NEET and JEE, built on the NCERT section "The mole and molar mass" in Some Basic Concepts of Chemistry. A balance pan of a chosen substance converts live into moles, molecules, and atoms of each element, with a stacked bar showing atoms per molecule. NEET has asked about this idea 4 times in 10 years of papers. JEE Main asked 45 questions from this chapter across the 42 shifts Lumi has analysed (2017–2026).
From the lesson The mole and molar mass in Some Basic Concepts of Chemistry. Change the values and watch what happens.
What it shows
NCERT § "Mole Concept and Molar Masses"
A balance pan of a chosen substance converts live into moles, molecules, and atoms of each element, with a stacked bar showing atoms per molecule.
Controls
3 to try
- Segmentedsubstance H2O / NH3 / CO2 / CH4 / O3
- Slidermass 0–100 g (0.1 g steps)
- Segmentedcount molecules / count H atoms / count all atoms
Try this
Choose a substance and mass so the sample holds exactly 1.5 mol of H atoms (e.g. 8.5 g NH3); goal checks |nH − 1.5| < 0.01.
Common mistake
Counting molecules when atoms of one element are asked: 0.5 mol NH3 has 1.5 mol H atoms, not 0.5.
In NEET
10 years of papers
Asked 4 times in 10 years of NEET.
See the past questions: Mole Concept, Some Basic Concepts of Chemistry (chapter)
In JEE Main
42 shifts analysed
45 questions from Some Basic Concepts of Chemistry across the 42 JEE Main shifts Lumi has analysed (2017–2026).
The idea behind it
NCERT § "Mole Concept and Molar Masses"
- The mole is the SI unit for amount of substance; one mole of anything contains 6.022 × 10²³ elementary entities (atoms, molecules, ions or formula units).
- This number is the Avogadro constant, Nᴀ = 6.022 × 10²³ mol⁻¹.
- Molar mass is how many grams one mole of a substance weighs; numerically it equals the atomic, molecular or formula mass in u (water: 18.02 u per molecule, 18.02 g mol⁻¹).
- Number of moles n = given mass / molar mass; number of particles = n × Nᴀ.
- Always check which particle is asked for: one mole of NH₃ has Nᴀ molecules but 3Nᴀ hydrogen atoms and 4Nᴀ atoms in total.
- For gases, NCERT's stoichiometry example takes one mole as 22.7 L, the molar volume of an ideal gas at 273.15 K and 1 bar; the older figure of 22.4 L belongs to 273.15 K and 1 atm.
Questions
5 answers
- What does the "From grams to moles to atoms" simulation show?
- A balance pan of a chosen substance converts live into moles, molecules, and atoms of each element, with a stacked bar showing atoms per molecule.
- What mistake does the "From grams to moles to atoms" simulation fix?
- A common mistake it clears up: counting molecules when atoms of one element are asked: 0.5 mol NH3 has 1.5 mol H atoms, not 0.5.
- Has NEET asked about this idea?
- Yes. NEET has asked about this idea 4 times in 10 years of papers.
- Does JEE Main ask questions from Some Basic Concepts of Chemistry?
- Yes. JEE Main asked 45 questions from this chapter across the 42 shifts Lumi has analysed (2017–2026).
- Is this simulation free?
- Yes. It is free and runs in the browser on a phone or a laptop. It belongs to the lesson "The mole and molar mass" in Some Basic Concepts of Chemistry (Class 11 Chemistry).
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