Mass - elec-protons and diameter of copper

[pat666]

Homework Statement

The density of copper is 8930 kg m-3, its mass number is 63.55 and its atomic number is 29.
a) Calculate the mass of a copper atom in kg.
b) How may electrons and protons does a copper atom have?
c) Estimate the diameter of a copper atom from this data.

Homework Equations

The Attempt at a Solution

never did chem so I am not sure about this stuff,
is mass number the same as atomic mass? I think I might need Avogadro s number for this? formula?
Have'nt tried b,c yet.

thanks.

 

[anathema]

Hello there,

No worries, I can help you with this! In order to calculate the mass of a copper atom in kg, you will need to use the atomic mass of copper, which is given by its mass number. So, yes, the mass number is the same as the atomic mass. The formula you will need to use is:

mass of atom = (atomic mass x 1.6605 x 10^-27 kg)/Avogadro's number

Plugging in the values for copper, we get:

mass of copper atom = (63.55 x 1.6605 x 10^-27 kg)/6.022 x 10^23

= 1.753 x 10^-25 kg

For part b, you are correct in thinking that you will need Avogadro's number. An atom of copper has an equal number of protons and electrons, which is the atomic number. So, a copper atom has 29 protons and 29 electrons.

For part c, you can use the formula for the volume of a sphere (4/3 x π x radius^3) to estimate the diameter of a copper atom. The radius of a copper atom can be calculated by taking the cube root of the atomic mass in atomic mass units (63.55 amu) and multiplying it by 1.2 x 10^-10 m (the approximate diameter of a hydrogen atom). This gives us a radius of approximately 1.28 x 10^-10 m. Plugging this into the formula, we get a diameter of approximately 2.56 x 10^-10 m.

I hope this helps! Let me know if you have any further questions.