# How many molecules in 2.5g of water?

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#1
^ help (please show working out lol)
0
3 years ago
#2
(Original post by L20Cg)
^ help (please show working out lol)
I mole of water is 18 g. This is the molar mass of H2O (16 for O plus 2 for 2 H).
So In 2.5 g you have 2.5/18 Moles of water. 2.5/18 * Avogadro constant gives you the number of molecules. This should be 8.37 x 10^22 molecules.
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3 years ago
#3
Extremely basic chemistry! It is taught at the beginning of every course that one molecule weigh one gram/
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3 years ago
#4
Molecular mass of H2O is 1+1+16=18
Number of moles = mass/molecular mass
= 2.5/18
=0.138 moles
1 mole is 6.02 x10^23 molecules
0.138 x 6.02 x 10^23 = 8.36 x 10^22 molecules
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3 years ago
#5
(Original post by Marxwasright)
Extremely basic chemistry! It is taught at the beginning of every course that one molecule weigh one gram/
One molecule doesn't weigh one gram
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3 years ago
#6
(Original post by joshchamp125)
One molecule doesn't weigh one gram
It does! My alevel teacher said so before my resit
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3 years ago
#7
(Original post by Marxwasright)
It does! My alevel teacher said so before my resit
One mole of hydrogen weighs 1 gram. One molecule is very small and weighs a lot less that 1 gram.
1
3 years ago
#8
(Original post by joshchamp125)
One mole of hydrogen weighs 1 gram. One molecule is very small and weighs a lot less that 1 gram.
1 mole is clearly one gram it says it on all the scales and I just check my school notes and it says it too.
0
3 years ago
#9
(Original post by Marxwasright)
Get educated, 1 mole is clearly one gram it says it on all the scales and I just check my school notes and it says it too. Some people are just ignorant!
Lol you're confidently stating false information. You're the ignorant one. One molecule doesn't weigh one gram. One molecule is so infinitisimally small you really think it weighs one gram? Do your research before spewing your false information on here
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3 years ago
#10
(Original post by joshchamp125)
Lol you're confidently stating false information. You're the ignorant one. One molecule doesn't weigh one gram. One molecule is so infinitisimally small you really think it weighs one gram? Do your research before spewing your false information on here
I do Alevel chemistry, I know. How dare you call me ignorant, no wonder the worlds average IQ is declining with dimwits like you, you diseducated omnishambles!
1
3 years ago
#11
(Original post by Marxwasright)
I do Alevel chemistry, I know. How dare you call me ignorant, no wonder the worlds average IQ is declining with dimwits like you, you diseducated omnishambles!
I'm done😂😂😂. You're deluded. If your chemistry teacher told you that there's no hope for you. Wonder how teaching standards can get that low. And if you wrote that in your resit you may have to resit chemistry yet again. Please google this and you will see I'm telling the truth.
0
3 years ago
#12
(Original post by joshchamp125)
I'm done😂😂😂. You're deluded. If your chemistry teacher told you that there's no hope for you. Wonder how teaching standards can get that low. And if you wrote that in your resit you may have to resit chemistry yet again. Please google this and you will see I'm telling the truth.
Mate, you cant even use grammar correctly, it is your not you're, get educated man!
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3 years ago
#13
(Original post by Marxwasright)
Mate, you cant even use grammar correctly, it is your not you're, get educated man!
This is sarcasm right? You're is short for you are, and it is right in the context.
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3 years ago
#14
(Original post by joshchamp125)
This is sarcasm right? You're is short for you are, and it is right in the context.
You serious? Why would it have an apostrophe in that case?
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3 years ago
#15
'1 mole is clearly one gram'

Well sh*t ive done chemistry all wrong
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3 years ago
#16
Just to highlight some equations that you should know OP:

(Original post by Marxwasright)
Extremely basic chemistry! It is taught at the beginning of every course that one molecule weigh one gram/
One mole of a molecule of hydrogen weighs one gram.
2
3 years ago
#17
'1 mole is clearly one gram'

Well sh*t ive done chemistry all wrong
Hahaha
0
3 years ago
#18
(Original post by Technetium)
Just to highlight some equations that you should know OP:

One mole of a molecule of hydrogen weighs one gram.
Finally someone agrees
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