Q.Write the multiple for the prefix mega.
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🔒 Start your 14-day free trial to unlock the full solution →Concept understanding — Law of Multiple Proportions
The Intuition: Why Nature Prefers Simple Ratios
Imagine you have a box of identical Lego bricks — all the same size and weight. You can build different structures by snapping them together. A simple tower might use 2 bricks per floor, while a wider tower uses 3 bricks per floor. The number of bricks in each floor is always a whole number — you can't use half a brick.
Atoms behave the same way. When two elements combine, they do so in fixed, discrete numbers of atoms. You can't have 1.5 atoms of oxygen bonding with 1 atom of carbon. It's either 1:1, 1:2, 2:1, or some other small whole-number ratio. This simple fact — that atoms are indivisible units in chemical combination — is the physical reason behind the Law of Multiple Proportions.
The Precise Statement
Law of Multiple Proportions (Dalton, 1803):
When two elements combine to form more than one compound, the masses of one element that combine with a fixed mass of the other element are in the ratio of small whole numbers.
Breaking It Down with an Example
Consider carbon and oxygen. They form two common compounds:
- Carbon monoxide (CO): 12 g of carbon combines with 16 g of oxygen
- Carbon dioxide (CO₂): 12 g of carbon combines with 32 g of oxygen
Fix the mass of carbon at 12 g (the same in both). The masses of oxygen that combine with it are 16 g and 32 g. Their ratio is:
3216=21
That's a small whole-number ratio (1:2). This is not a coincidence — it reflects the fact that CO has one oxygen atom per carbon, while CO₂ has two.
Another Classic: Nitrogen Oxides
Nitrogen and oxygen form several compounds. Fix 14 g of nitrogen (one mole of N atoms):
| Compound | Formula | Mass of O combining with 14 g N | Ratio of O masses |
|---|---|---|---|
| Nitrous oxide | N₂O | 8 g | 1 |
| Nitric oxide | NO | 16 g | 2 |
| Nitrogen dioxide | NO₂ | 32 g | 4 |
| Dinitrogen pentoxide | N₂O₅ | 40 g | 5 |
The oxygen masses (8, 16, 32, 40) are in the ratio 1:2:4:5 — all small whole numbers.
A common mistake is to think the law applies to any two masses in a compound. It does not. The law only compares masses across different compounds formed by the same two elements, with the mass of one element held fixed.
Why This Matters …
In the SI system of prefixes, 'mega' (symbol M) denotes a multiplying factor of 10^6, e.g. 1 …
[!TLDR]
10^6
Method
In the SI system of prefixes, 'mega' (symbol M) denotes a multiplying factor of 10^6 …
- CBSE 2026Set ANNUAL1 markMCQQ.The law of multiple proportion was propounded by(a) Dalton(b) Berzelius(c) Graham(d) Priestley
›Reveal solutionSolution
The law of multiple proportions was given by John Dalton.
The law of multiple proportions (1803) states that if two elements form more than one compound, the different masses of one element combining with a fixed mass of the other bear a simple whole-number ratio. Example: in CO and …
- CBSE 2023Set ANNUAL1 markQ.State the law of multiple proportion.
›Reveal solutionSolution
Law of multiple proportions: when two elements form more than one compound, the masses of one element per fixed mass of the other are in a small whole-number ratio.
Law of multiple proportions (Dalton): If two elements combine to form more than one compound, the different masses of one element that combine with a fixed mass of the other element bear a simple ratio of small whole numbers to one another.
…
- CBSE 2021Set ANNUAL1 markQ.State the law of multiple proportions.
›Reveal solutionSolution
When two elements form more than one compound, the masses of one element combining with a fixed mass of the other are always in a simple whole-number ratio — this is Dalton's law of multiple proportions.
Proposed by John Dalton, the law of multiple proportions states: if two elements can combine to form more than one compound, the masses of one element that combine with a fixed mass of the other element are in the ratio of small whole numbers.
…
- CBSE 2020Set ANNUAL1 markQ.Write the multiple for the prefix mega.
›Reveal solutionSolution
[!TLDR]
10^6
Method
In the SI system of prefixes, 'mega' (symbol M) denotes a multiplying factor of 10^6 …
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