1
vote
2answers
104 views

Why is density an intensive property?

I am still trying to understand what are intensive and extensive properties. Possibly someone can give a pointer to a decent text (preferably on the web), as I am not too happy (to say the least) with ...
-1
votes
1answer
91 views

Boundary conditions for the heat equation when solving a mass density gradient

I'm working with a mass density gradient with length $L$ and I'm trying to solve the heat equation in 1-D (mass diffusion equation, $\partial_t\rho(t,x)=D\Delta\rho(t,x)$), but I'm not sure which ...
0
votes
1answer
48 views

Density as a function of Temperature?

I know that volume = mass/density....and density is the function of temperature. Is there any standard equation that describes density as a function of temperature? The system I am interested in is ...
3
votes
2answers
127 views

Pressure versus Volume system problem

A rigid air tight container of volume 1.5 m$^3$ is filled with a gas of density 8 kg/m$^3$. The container has a density meter that allows us to watch the changes in density in the gas in the ...
2
votes
1answer
80 views

Does salt $NaCl$ as a solid float in molten salt?

I know ice floats in water because it's crystalline structure causes $H_20$ solid to be less dense than $H_20$ liquid. Is the same true for salt because it is crystalline? If not why?
3
votes
3answers
301 views

Why is gas(oline) in gas stations sold by volume (as opposed to mass)?

Fluids (including natural gasoline/petroleum) have variable volume based on the ambient temperature for the same mass of fluid. So, really, the amount of gas that you're filling your car with depends ...
0
votes
3answers
292 views

Temperature and density

As temperature rise the density become lower,When temperature goes down, density is higher but in higher temperature the body become bigger so why density become lower?
3
votes
3answers
2k views

How can I determine density of a gas only given temperature?

I have a homework problem where exhaust is traveling through an exhaust system (assumed to be air for simplicity) from and engine and then released into the atmosphere. The exhaust is at a temperature ...
3
votes
2answers
318 views

Density of states via a Laplace transform

Is this formula correct? $$ \frac{-1}{\pi}Im\int_{0}^{\infty}\!dt~\exp(Et)\Theta (t)\exp(i \epsilon t) ~=~ \sum _{n}\delta (E-E_{n}), $$ $$ \Theta (t)~=~ \sum_{n}\exp(-tE_{n}) ,$$ and I have used ...