How Many Atoms are in a Regular Loaf of Bread?

[BISMARCK]

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?

[Swift]

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.

[djellison]

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

[BISMARCK]

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

[Nick Theodorakis]

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

[Swift]

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?

[Bozola]

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

[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.

[Swift]

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!"

[pghnative]

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]

[BISMARCK]

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?

[cjl]

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

[Jim]

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

How many atoms are in the loaf?

Enough.

[Jens]

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.

[BISMARCK]

Yeah, that's true too.

[Stuart van Onselen]

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.

[novaderrik]

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?

[geonuc]

Even the hyper-inflation of Zim ...

Zim has been inflated? Is he now one of The Tallest?

[John Jones]

Why hasn't anyone mentioned Avogadro's number?

http://en.wikipedia.org/wiki/Avogadro's_number

[geonuc]

Why hasn't anyone mentioned Avogadro's number?

http://en.wikipedia.org/wiki/Avogadro's_number

It's been used here.

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.