# Density of the carbon atom

#### omni

think that all the mass of the atom are concentrate in nucleus
and the shape of the nucleus is like a ball with
radius =1.5*10^5. IF the mass of the carbon atom = 2.0*10^23.
what is the density of the carbon atom?
the volume of the planet Earth=4/3pie*r^3

i just want to say that my English is not so good so i hope u can understand my question.

thanks you all.

#### cepheid

Staff Emeritus
Gold Member
Welcome to Physics Forums,

From now on, use the template given for homework help problems. You have given us the problem statement, now what are some relevant equations that would apply here? Also, most importantly, show us your attempt. What have you done so far on this problem?

You have stated a mass and a volume without units, which means these numbers are meaningless. WHAT UNITS are the mass and radius in?

What is the definition of density?

#### omni

hi thanks for ur remark.
ok so the units is:radius =1.5*10^5pm
the mass of the carbon atom =2.0*10^23.gr

i tried to use in this formula: d=m/v
m=mass
d=density
v=volume
i did like this:d=2.0*10^23.gr/1.5*10^5pm.
and i not sure if i right.

i will be happy for any help that i can get :).

#### cepheid

Staff Emeritus
Gold Member
Does .gr mean, "grams" or...?

Your calculation steps are right so far, but you need to
1) actually calculate the final answer, and
2) express it in some reasonable units. For example, density is often expressed in kg/m3 or g/cm3. Do you know which units you are expected to use?

EDIT: In fact you have to decide (2) before you do (1), since you need to convert the numbers into the desired units before computing the final answer.

#### omni

ok i will try to keep from here alone thank you really much i think i understand this question.

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