Question

Very small crystals composed of 1000 to 100,000 atoms, called quantum dots, are being investigated for use in electronic devices.
(a) Calculate the mass in grams of a quantum dot consisting of 1.400 104 atoms of silicon.
(b) Assuming that the silicon in the dot has a density of 2.3 g/cm3, calculate its volume.
(c) Assuming that the dot has the shape of a cube, calculate the length of each edge of the cube.

Answer 1

How many moles Si in the dot?
1.400 x 10^4 atoms/6.022 x 10^23 = ??moles.
Convert that to grams.
?? moles x molar mass Si = grams.

#2. mass = volume x density.
You have mass and density, calculate volume.

3. volume = length^3; calculate length.
Post your work if you get stuck.