# Thread: How Many Atoms are in a Regular Loaf of Bread?

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## How Many Atoms are in a Regular Loaf of Bread?

Let's say this is a simple loaf of bread that is .5kg.

Do any of you know how to get a ballpark figure for how many atoms are in the loaf? I'd assume that carbon atoms make up most of the mass, right?

2. If bread was all carbon, then 0.5 kg (500g), divided by the atomic weight of carbon (12 g/mole) is 41.7 mole. One mole contains 6.02 x 1023 atoms, so you have 2.5 x 1025 atoms in your loaf of bread.

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Well- the ballpark way to do it is to imagine the 'average' molecular mass of whatever is in the bread. Bread is going to be packed full of a lot of complex compounds- which will, mainly, contain Carbon, Oxygen, Hydrogen and Nitrogen.

But - as a very very very bad ballpark - what would 500g of Carbon be in terms of atoms?

There is a unit of matter called a 'mole'. This is an ammount of an element or compound in grammes, equal to its total atomic weight. Carbons atomic mass is 12.0107 (that's the average mass of a Carbon atom based on the various isotopes of carbon that exist)

One 'mole' of Carbon is thus 12.0107 grammes. 500g is thus 41.63 moles of carbon.

The great thing is - a mole ends up being a known number of atoms - a number called Avegadros constant - 6.02214179×10^23.

Thus - 41.63 moles, of 6.02 *10^23 is...

2.50 * 10^25 atoms of carbon in 0.5 kg of carbon.

However - that is a HUGE simplifcation of how many atoms are in a loaf of bread. Bread will be made up of many many complex and heavy organic compouds, as well as a not insignificant number of atoms of gas in the bubbles of air (or probably CO2 from the yeast during the baking process ). But - those organic compounds will be made from C, N, O and H (often in a ratio of around 1 C and 1 O to 2 H's ) - those H's will actually reduce the average mass of the atoms I would expect, so there may be significantly more atoms than the rough estimation of just using Carbon.

I'm guessing this is a homework question, right

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Ha, no, actually it's part of a punchline in a very obtuse joke. It would take a while to explain.

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Looking at some typical "Nutrition Facts" labels, it seems that to a first approximation, bread has about half its weight in carbohydrate, which has an approximate ratio of C:H:O of 1:2:1. It may have about 5-10% in protein, and a few percent fat. I imagine the rest is probably water.

Nick

6. If we wanted a very slightly more complex model of bread, lets say it was made of glucose (a simple sugar), instead of carbon. Glucose is C6H12O6, with a molecular weight of 180. That means our 500 g of glucose is 2.78 moles, or 1.67x1024 molecules of glucose. Since glucose has 24 atoms, that works out to 4.01x1025 atoms; not very different from the estimate based on carbon.

Have we killed your joke yet?

7. Just one basic particle, massively looping in space-time.

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Ok, thanks for the answers. What I'm getting at is that a loaf of bread on the black market of Zimbabwe costs 10 billion Z-dollars, which of course is absurd.

So I was interested to see exactly what one Z-dollar could by. I figured it would get you a handful of molecules.

9. Originally Posted by BISMARCK
Ok, thanks for the answers. What I'm getting at is that a loaf of bread on the black market of Zimbabwe costs 10 billion Z-dollars, which of course is absurd.

So I was interested to see exactly what one Z-dollar could by. I figured it would get you a handful of molecules.
I assume you are using 109 for billion, so you are talking about 1015 atoms of bread per Z-dollar.

Oh wait, I have a coupon for "Buy 1010 atoms, get 105 free!"

10. Originally Posted by Swift
I assume you are using 109 for billion, so you are talking about 1015 atoms of bread per Z-dollar.

Oh wait, I have a coupon for "Buy 1010 atoms, get 105 free!"
[nitpick]Who gets the other 9.999899999*10E14 atoms[/nitpick]

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Originally Posted by Swift
I assume you are using 109 for billion, so you are talking about 1015 atoms of bread per Z-dollar.

Oh wait, I have a coupon for "Buy 1010 atoms, get 105 free!"

Right, I came to the same conclusion, that one Z-dollar would get me 4 x 10^15 atoms of bread, which is 4,000,000,000,000,000 atoms. Roughly speaking how many grams is that, if we're talking about glucose molecules?

12. Not many.

Glucose has a molecular weight of 180, which means 1 mole of glucose weighs 180 grams. However, one mole has 6.022*1023 atoms, so you only have 6.6*10-9 moles. So, you have 180*6.6*10-9 grams, or 1.18 micrograms

13. Sheesh, the math, the machinations... The answer is simple.

How many atoms are in the loaf?

Enough.

14. Originally Posted by BISMARCK
Right, I came to the same conclusion, that one Z-dollar would get me 4 x 10^15 atoms of bread, which is 4,000,000,000,000,000 atoms. Roughly speaking how many grams is that, if we're talking about glucose molecules?
I don't think you need to deal with the atoms to do that. Just take the weight of the loaf, and divide by a billion.

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Yeah, that's true too.

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Atoms are tiny.

Really, really tiny.

Even the hyper-inflation of Zim fails to provide a useful scale for us to grasp their insane tinyness.

They're just that tiny.

17. are you guys counting the molecules of air that are trapped in all the little bubbles that make up most of the area that the loaf of bread inhabits?

18. Originally Posted by Stuart van Onselen
Even the hyper-inflation of Zim ...
Zim has been inflated? Is he now one of The Tallest?

19. Why hasn't anyone mentioned Avogadro's number?

20. Originally Posted by John Jones
Why hasn't anyone mentioned Avogadro's number?