# Need a formula

Hello Experts. I need help finding the formulas for the following questions:

What is the mass in kg of 2.0 m^3 of Br_2?
What is the volume in mL of 10.5 g of Br_2?

Not looking for the answers, I really need to learn this! Just looking for a starting point.

Thanks.
###### Who is Participating?

Commented:
What is the density of Br_2?
mass in g is density * volume in cm^3
cm^3 = mL

That should be all you need to solve the problem.
0

Commented:
You can check your work with wolframalpha
http://www.wolframalpha.com/input/?i=mass+of+2+m^3+of+Br_2
0

Commented:
I am not sure what you mean by Br_2
-
In any case, if you know the volume of anything and the density you can find the mass.
mass = density x volume
so for your first question you need to find in some way the density.

The second uses the same idea, find the density and use the same equation stated above.

Now you may have a difficulty with the density of Br_2.  If that is a problem I need  need to know exactly what the Br_2 means.
0

Commented:
Bromine.
You (horalia) should have a table in your book that tells you what density it is.
Of course, being that this is an academic question, we probably have given as much info as we should at this point until the asker comments again.
0

Commented:
Bromine. .....
exactly but in what form?
I was trying to get him to state or find the conditions. It makes a big difference whether you are dealing with a solid of gas
0

RetiredCommented:

ChemTeam - A Tutorial for High School Chemistry: The Standard States of the Elements
All chemical substances are either solid, liquid or gas. To make comparisons easier, the chemistry community has agreed on a concept called "the standard state." The standard state of a chemical substance is its phase (solid, liquid, gas) at 25.0 °C and one atmosphere pressure. This temperature/pressure combo is often called "room conditions."

Two elements are liquid in their standard state: mercury and bromine.

Eleven elements are gas in their standard state. All of the noble gases (He, Ne, Ar, Kr, Xe, Rn) as well the halogens fluorine and chlorine. Hydrogen, oxygen and nitrogen are the others.

All other elements are solid in their standard state.
So the exact answers to your questions will depend on the exact values of temperature and pressure in which the measurements are taken!
0

Commented:
From the problem wording, I suspect that the temperature and pressure are such that bromine is a gas. if so, you are probably supposed to solve the Ideal Gas Law formula (pV = nRT) for the unknown number of moles or volume. From the number of moles and atomic weight, you can calculate the mass.

If temperature and pressure are such that bromine is a liquid, then you need to look up the density of the liquid. Liquid density correlations are empirical, rather than derived from first principles.
0
Question has a verified solution.

Are you are experiencing a similar issue? Get a personalized answer when you ask a related question.

Have a better answer? Share it in a comment.