How Many Molecules of CO2 and Water Vapour Are in 1 Cubic Metre of Air?

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Discussion Overview

The discussion revolves around calculating the number of molecules of CO2 and water vapour in one cubic metre of air, based on given concentrations in parts per million (ppm) and the total number of molecules in that volume. Participants are exploring the implications of ppm and the calculations involved in determining the quantities of these gases.

Discussion Character

  • Homework-related
  • Mathematical reasoning
  • Conceptual clarification

Main Points Raised

  • One participant states that 1 m3 of atmosphere at sea level contains 3.80 × 102 ppm of CO2 and 5.00 × 103 ppm of water vapour, and asks for help with calculations.
  • Another participant clarifies that 3.80 × 102 ppm means 380 ppm (parts per million).
  • A participant questions how much carbon dioxide would be present in a million cubic metres of atmosphere, suggesting a simple calculation.
  • There is a discussion about the relationship between the number of molecules and the volume they occupy, with one participant correcting another's assumption about the number of molecules in a given volume.
  • Participants engage in calculations to determine how many molecules of CO2 would be present in a much larger sample size, referencing the total number of molecules in 1 m3 of air.
  • One participant expresses uncertainty about their calculations, indicating a lack of confidence in their mathematical skills.
  • Another participant prompts further exploration of basic division to understand how many millions fit into larger numbers.

Areas of Agreement / Disagreement

The discussion contains multiple viewpoints and calculations, with no consensus reached on the final answer or methodology. Participants are exploring different aspects of the problem without agreeing on a single approach or solution.

Contextual Notes

Participants are working through the implications of ppm and the calculations required to derive the number of molecules from given concentrations. There are indications of confusion regarding the relationship between volume and the number of molecules, as well as uncertainty in mathematical reasoning.

Who May Find This Useful

This discussion may be useful for students learning about gas concentrations, ppm, and basic calculations in chemistry or environmental science.

alytal
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One cubic metre (1 m3) of atmosphere at sea level contains 3.80 × 102 ppm of CO2 and 5.00 × 103 ppm of water vapour.
If there is a total of 2.6 × 1025 molecules in 1 m3 of air, calculate how many molecules of CO2 and water vapour there are in 1 m3 of air??

I just starting studying science and i´m stuck with this simple question..please help!
 
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alytal said:
One cubic metre (1 m3) of atmosphere at sea level contains 3.80 × 102 ppm of CO2 and 5.00 × 103 ppm of water vapour.
If there is a total of 2.6 × 1025 molecules in 1 m3 of air, calculate how many molecules of CO2 and water vapour there are in 1 m3 of air??

I just starting studying science and i´m stuck with this simple question..please help!

What does 3.80 × 102 ppm mean?
 
sjb-2812 said:
What does 3.80 × 102 ppm mean?

it means 380 ppm (parts per million)
 
alytal said:
it means 380 ppm (parts per million)

So, if you had a million cubic metres of atmosphere, how much of that would be carbon dioxide?
 
sjb-2812 said:
So, if you had a million cubic metres of atmosphere, how much of that would be carbon dioxide?

380 molecules of co2...is that simple the answer??
 
alytal said:
380 molecules of CO2...is that simple the answer??

No, not to the question I posed. 1 molecule does not occupy 1 m3.

However, if you had a million molecules, then yes, for this sample you would have 380 molecules of carbon dioxide. Now, how many times larger is 2.6 × 1025, compared to 1 million; or if you prefer how many millions are there in a sample that size?
 
sjb-2812 said:
No, not to the question I posed. 1 molecule does not occupy 1 m3.

However, if you had a million molecules, then yes, for this sample you would have 380 molecules of carbon dioxide. Now, how many times larger is 2.6 × 1025, compared to 1 million; or if you prefer how many millions are there in a sample that size?

So... (380 x 1025) / 106 = 988 x 10[19] ??
I´m very bad..i know...
 
Not quite, how many millions are there in 2,000,000?
 
sjb-2812 said:
Not quite, how many millions are there in 2,000,000?

two...
 
  • #10
How many millions in 5 x 109?
 

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