Question: How Many Atoms are in a A4 piece of paper?

Oliver Gordon answered on 13 Mar 2019: last edited 14 Mar 2019 7:05 am

Sorry I couldn’t answer this earlier – I only just got the question through!! I didn’t forget you!
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First off, we need to think of the volume of a piece of paper. Let’s take some normal A4. The surface area is 297 x 210 mm, for a total surface area of 62370 square mm, or 0.062 square metres. While the depth of it depends on the quality of paper, lets take normal standard paper – 80gsm (80 grams per squ
re meter). Dividing it through, we get the piece of paper weighing about 5 grams.
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Now, what atoms make up the paper? Well, paper is made from wood, which is mostly carbon. So lets just assume it’s 100% carbon – we’re only guessing here!.
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So we can then divide the 5 gram mass by the atomic mass of carbon, which, according to the periodic table is 12 atomic units. We can turn atomic units into grams by dividing by 6.022e+23 (known as the Avagadro constant, which is the number of atoms in what is known as a “mole”). So 5*6.022e+23/12. This is about 3×10^24 (aka 3000000000000000000000000) atoms in a piece of A4 paper)