Question

Please help in any way that you can.

Very small spherical crystals called quantum dots are being investigated for use in electronic
devices.
a. Calculate the mass of a quantum dot of pure silicon that has a diameter of 4nm.
b. If you made a 3.5nm diameter quantum dot of pure germanium, how many
germanium atoms would it contain?

Answer 1

a. volume of sphere = (4/3)*pi*r^3
You need the volume in cc; therefore, I would convert 4 nm to cm and go from there.(Note: 1 nm = 10^-9 m; 1 m = 100 cm) Then mass = volume x density. You will need to look up the density in your text or on-line.

b.
Use the same procedure as in a and convert 3.5 nm to grams. Then remembering that 1 mol Ge contains 6.02E23 atoms, calculate # atoms in the mass of Ge.

Answer 2

i got
A) 7.0*10^6
B) 2.4*10^6
is this right

Answer 3

If you will show your work I will look for the error(s). And what are the units.