How many water moleucles ...

[xouper]

This week's science quiz:


Approximately how many water molecules are in one fluid ounce?

Hint: If you stick to one or two significant digits, you can do this without a calculator.

http://www.xoup.net/faq/watermolecules.php

[viscousmemories]

Hmm... well we know that a molecule is one molianth of a cule, and a fluid ounce is approximately 1000 cules... So I'm gonna guess there are 1000 molianth cules of water in a fluid ounce. :yup:

[livius drusus]

You are such a cule, vm. :giggle:

I have to admit I didn't even try to work out the answer, xoup. Instead I just read your explanation, remembered my 10th grade Chemistry exam and felt like a total dumbass for forgetting it all.

[JoeP]

Hint: If you stick to one or two significant digits, you can do this without a calculator.

Only for freaks who remember Avogadro's number. :P

I may be a freak for even remembering there is an Avogadro's number :mole:

[ceptimus]

I refuse to work with fluid ounces. They're not only used for fluids, and they usually don't weigh an ounce. What a stupid unit of measurement! :fuming:

Also (nitpick) what's a moleucle? is that the American version of a molecule? :P

But I do remember Avagadro's number... :smugnod:

[viscousmemories]

Whoa! I can't believe livius or I didn't notice that typo first. Freaky! :eek:

[Ensign Steve]

I refuse to work with fluid ounces. They're not only used for fluids, and they usually don't weigh an ounce. What a stupid unit of measurement! :fuming:

No kidding! When my Olivia was cooking, she would try to use the 8 oz in a cup and the 16 oz in a pound interchangeably. She would try to convert 1/4 pound of shredded cheese to 1/2 cup unless I ran in and rescued her. Scary!

[slimshady2357]

Well, one fluid ounce is about .03 litres, which, when dealing with water is about 30 grams.

(as a side note, some people may not know that you can use google as a unit converter, just type in something like "fluid ounce in litres" and it will not do a search, it will come up with a page like this (http://www.google.co.uk/search?hl=en&q=fluid+ounce+in+litres&meta=))

A mole of water weighs about 18 grams, so there are 30/18 = 5/3 = 1 2/3 moles of water in 30 grams.

That means there should be about (6.02 x 10^23) x (1 2/3) = 1.03 x 10^24 molecules of water in one fluid ounce.

I hope that's right :)

I used google for only one thing, how many grams are there in a fluid ounce. And as xouper suggested, no calculators are needed. ;)

Adam

[livius drusus]

Oh so what do you think you're better than me? Huh? Huh? Do ya? :bull:

[slimshady2357]

No, no, not at all! I don't think so at all :giggle:

:P :P :P

Adam

(now I'm sure to have gotten it wrong :blush:)

[livius drusus]

Well at least I know enough to click on the spoiler box to get the answer. :madrazz:


:giggle:

[xouper]

... what's a moleucle?
Bait. :D

[Dingfod]

A bazillion times a gazillion?

[xouper]

slimshady2357: I used google for only one thing, ...
Perhaps a good quiz question requires more than just googling for factoids, one must still know how to put them all together. :)

I just now googled (http://www.google.com/search?q=%22how+many+water+molecules%22+ounce) for

"how many water molecules" ounce

and got seven hits, including this one which contains various versions of the answer:

http://www.newton.dep.anl.gov/askasci/chem03/chem03149.htm

:doh: