How Do Nitrogen Molecules Separate When Changing From Liquid to Gas?

  • Thread starter Thread starter JasonRox
  • Start date Start date
Click For Summary

Homework Help Overview

The discussion revolves around the transition of nitrogen molecules from liquid to gas, specifically focusing on the change in molecular separation during this phase transition. The problem involves calculations related to the densities of liquid and gaseous nitrogen and seeks to understand the implications of these densities on molecular spacing.

Discussion Character

  • Exploratory, Conceptual clarification, Mathematical reasoning

Approaches and Questions Raised

  • Participants discuss the relationship between the densities of liquid and gas nitrogen and how to calculate the increase in molecular separation. There are attempts to clarify the volume of a liter in cubic meters and the implications of density on the calculations. Some participants express confusion over their results compared to the expected values in the book.

Discussion Status

The discussion is active, with participants sharing their calculations and reasoning. Some have provided helpful clarifications regarding unit conversions and density relationships, while others are questioning their own results and seeking validation. There is no explicit consensus on the correct approach or outcome yet.

Contextual Notes

Participants note the lack of specific mass information for the liquid nitrogen and express frustration over the clarity of the problem as presented in the book. There is also mention of the context of the problem being from an old physics book, which may contribute to the confusion.

JasonRox
Homework Helper
Gold Member
Messages
2,394
Reaction score
4
This is a question in my book.

Density of Liquid Nitrogen 804 grams per litre.

Density of Nitrogen Gas 4.4 grams per litre.

Calculate the increase in the separation of nitrogen molecules from the liquid to vapour states.

Note: Can someone tell me how many cubic metres there is in a litre.
 
Physics news on Phys.org
A liter is one cubic decimeter, so there are 10 x 10 x 10 liters (that's 1000, just in case you don't have a calculator!) in a cubic meter.
 
[tex]1 litre = 1000 cm^3[/tex]
[tex]1 cm = 10^{-2} m[/tex]
[tex](1 cm)^3 = (10^{-2} m)^3[/tex]
[tex]1 cm^3 = 10^{-6} m^3[/tex]

[tex]1000 cm^3 = 10^{-3} m^3[/tex]

[tex]1 litre = 10^{-3} m^3[/tex]

Use the density formula,

[tex]\rho = \frac {m}{v}[/tex]
Consider m mass of some liquid nitrogen and get the volume increase in percentage since no definite mass of liquid nitrogen is given. The mass of the liquid nitrogen doesn't change when it vapours to the gas form.

Doing other's homework is strictly not encouraged here. so, try it yourself first. when you are stuck, post what you have done here and help will come. good luck.
 
It's not my homework for gods sake. It's in an old physics book I bought at a second hand store.

I did try it, and I got 182x more distant, but the book says 5.7x, so I wanted to see where my mistake was. Knowing what a litre is(in metres), which the book did not explain would certainly help a little.

I understand that you don't like doing peoples homework, but it isn't even school season. Sheesh!
 
i guess you don't like what i have said here. anyway, i got the same answer as your.
 
look, when you have 1Liter of nitrogen gas, this contains 4.4 grams ; now imagine how many Liters do you need for 804 grams => (V/804)=(1L/4.4) => V=804/4.4 Liters = 182.7272... Liters and also V=l^3 => l=(V)^(1/3) => l=(182.7...)^(1/3) = 5.6745...~5.7.
wisky40
 
Thanks! That helps me out.
 
Let
[tex]x_{g}= N_{2}[/tex] molecules' separation in gas form
[tex]x_{l}= N_{2}[/tex] molecules' separation in liquid form

[tex]\frac{x_{g}^3-x_{l}^3}{x_{l}^3} = 182[/tex]
[tex]\frac{x_{g}}{x_{l}}= 5.7[/tex]
 

Similar threads

Replies
15
Views
3K
Replies
1
Views
3K
  • · Replies 11 ·
Replies
11
Views
2K
Replies
1
Views
5K
  • · Replies 7 ·
Replies
7
Views
3K
Replies
2
Views
2K
Replies
5
Views
2K
  • · Replies 3 ·
Replies
3
Views
7K
  • · Replies 6 ·
Replies
6
Views
3K
  • · Replies 8 ·
Replies
8
Views
8K