Question

give the radii of the following in meter molecule of hemoglobin and grain of sand

Answer 1

Short answer: ~ 50 000 000 000 000 000 000 atoms.

50 quintillion (short scale) in the US, Canada or UK.

50 trillion (long scale) in the civilized part of the world... ;)

50 hexillion if you like greek (not a standard).

50 million million million atoms, some would say.

50 x 10^18 is another way to write it, although:

5 x 10^19 atoms would be the standard expression.

Long answer: It varies.

There's roughly in the neighbourhood of 1 - 100 quintillion/trillion atoms. Quite possibly more, quite possibly even less.

That's 1 - 100 million million million atoms.

Sand is made up of different materials, making it difficult to do a generalized calculation.

However, the most frequently mentioned material is silicon dioxide, or SiO2.

The atomic weight of Si (Silicon) is 28 units.

The atomic weight of O(Oxygen) is 16 units.

That puts the atomic weight of SiO2 at 28 + 2 x 16 = 60 units.

Avogadro tells us that we have 6.023 x 10^23 SiO2 units per gram, so there would be 6.023 x 10^23 / 60 ≈ 1 x 10^22 SiO2 units in a gram of pure SiO2, and with SiO2 composed of 3 atoms, that puts us at 3 x 10^22 atoms per gram of SiO2.

Now, a grain of sand does not weigh 1 gram. It weighs less. So we continue:

Sand is defined as having a size between 0.0625 mm and 2 mm.

Say a grain of sand is shaped like a cube, with each side exactly 1 mm in length. It then has a volume of 0.001 cm^3. This is not fine sand.

1 cm^3 of SiO2 weighs about 2.65 g  

Our little cube of "sand" then weighs 0.00265 g

To find the number of atoms in this cube we then multiply this weight with the number of atoms in a gram of SiO2.

3 x 10^22 x  0.00265 = 7.95 x 10^19 atoms

So, our little cube holds 79.5 quintillion/trillion atoms.

Given the size and composition variations, even the range estimation given above of 1 - 100 quintillion/trillion is going to be inaccurate, but I hope this answer still gives you an idea of the numbers we are dealing with.

Answer 2

Answer:

Short answer: ~ 50 000 000 000 000 000 000 atoms.