The Student Room Group
Uni students - Complete our survey >>
Uni students - Complete our survey >>
Uni students - Complete our survey >>

This discussion is now closed.

Check out other Related discussions

The Super Juicy CURRENT YEAR 11 (2012-13) THREAD Mark VI

Scroll to see replies

will somebody give me a step by step answer to this question

15cm3 of ethanoic acid was neutralised by 45cm3 of NaOH of concentrration 0.2 molesdm-3

calculate the concentration of the ethanoic acid in grams per decimetre?

i can do it when it just says moles per deimetre but the last step from the CGP book baffles me -_-
Original post by techno836
will somebody give me a step by step answer to this question

15cm3 of ethanoic acid was neutralised by 45cm3 of NaOH of concentrration 0.2 molesdm-3

calculate the concentration of the ethanoic acid in grams per decimetre?

i can do it when it just says moles per deimetre but the last step from the CGP book baffles me -_-

Devide all the volumes in cm3 by 1000 to get them in dm3 :smile:



Posted from TSR Mobile
(edited 10 years ago)
Original post by techno836
will somebody give me a step by step answer to this question

15cm3 of ethanoic acid was neutralised by 45cm3 of NaOH of concentrration 0.2 molesdm-3

calculate the concentration of the ethanoic acid in grams per decimetre?

i can do it when it just says moles per deimetre but the last step from the CGP book baffles me -_-


Concentration = Number of Moles / Volume

So how many moles of NaOH?

Write out the balanced equation.

How many moles of NaOH for Ethanoic Acid?

Whatever it is scale the moles up.

Concentration = Number of Moles / Volume

Find the concentration.

Then

Mass in g = moles x Mr

= mass in g/dm^3
Original post by L'Evil Fish
Concentration = Number of Moles / Volume

So how many moles of NaOH?

Write out the balanced equation.

How many moles of NaOH for Ethanoic Acid?

Whatever it is scale the moles up.

Concentration = Number of Moles / Volume

Find the concentration.

Then

Mass in g = moles x Mr

= mass in g/dm^3

I got 24296 g/dm3 and that really doesnt seem right?
Wait a sec i think I know where i went wrong...
(edited 10 years ago)
Original post by sammann123
I got 24296 g/dm3 and that really doesnt seem right?
Wait a sec i think I know where i went wrong...


Probably didn't divide by the 1000
Original post by L'Evil Fish
Concentration = Number of Moles / Volume

So how many moles of NaOH?

Write out the balanced equation.

How many moles of NaOH for Ethanoic Acid?

Whatever it is scale the moles up.

Concentration = Number of Moles / Volume

Find the concentration.

Then

Mass in g = moles x Mr

= mass in g/dm^3


This stuff was the only part of Chemistry I was actually good at :mmm:
Original post by justinawe
This stuff was the only part of Chemistry I was actually good at :mmm:


It's actually my worst bit atm:wink:
Original post by L'Evil Fish
Probably didn't divide by the 1000

nope, made a stupid mistake in working out the no. mols
Original post by L'Evil Fish
Concentration = Number of Moles / Volume

So how many moles of NaOH?

Write out the balanced equation.

How many moles of NaOH for Ethanoic Acid?

Whatever it is scale the moles up.

Concentration = Number of Moles / Volume

Find the concentration.

Then

Mass in g = moles x Mr

= mass in g/dm^3



36g ?


0.045 x 0.2 = 0.009 Moles
0.009 /0.015 = 0.6 molesdm-3
(12+3+12+18+18+1) = 60
so i then do mass per decimeter = 0.6 x 60 = 36g per deciimetre ?
Original post by L'Evil Fish
Probably didn't divide by the 1000

36 g/dm3 sounds like a much better answer:smile:
Original post by techno836
36g ?


0.045 x 0.2 = 0.009 Moles
0.009 /0.015 = 0.6 molesdm-3
(12+3+12+18+18+1) = 60
so i then do mass per decimeter = 0.6 x 60 = 36g per deciimetre ?

yeah thats what i just got
Original post by sammann123
nope, made a stupid mistake in working out the no. mols


Original post by techno836
36g ?


0.045 x 0.2 = 0.009 Moles
0.009 /0.015 = 0.6 molesdm-3
(12+3+12+18+18+1) = 60
so i then do mass per decimeter = 0.6 x 60 = 36g per deciimetre ?


Original post by sammann123
36 g/dm3 sounds like a much better answer:smile:


I myself don't know the answer :rofl:

I just gave you general steps and hoped it'd work :yy:
Sounds right though
Original post by L'Evil Fish
I myself don't know the answer :rofl:

I just gave you general steps and hoped it'd work :yy:
Sounds right though

Yeah if we both got the same thing and its a round number its most likely right!
Original post by sammann123
Yeah if we both got the same thing and its a round number its most likely right!


:yep: hi btw, don't think we've spoken?
Original post by sammann123
yeah thats what i just got


right CGP seriously made the grams part look overcomplicated -_-
:moon:
Original post by L'Evil Fish
:yep: hi btw, don't think we've spoken?

Nope I don't believe we have!
Original post by sammann123
Nope I don't believe we have!


Well hello :wavey: :mmm:
GOOD LUCK FOR THE LITERATURE EXAMS PEOPLE! :goodluck:
Original post by JustaDreamer
GOOD LUCK FOR THE LITERATURE EXAMS PEOPLE! :goodluck:


Thanks, good luck to you too!


Posted from TSR Mobile

Related discussions

Latest

Trending

Trending

Articles for you