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# Chemical Equation watch

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1. I am required to obtain an accurate value of molarity (concentraton) of a given solution of Sodium Hydroxide. The Standardisation is carrid out by titration against a known and accurate weight of the primary standard KHP (Given Mr: 204.22)

Mass of KHP/g = 0.6002
NaOH titre value 1/ml = 29.85 ml

What s the Molarity of the NaOH solution?

Any help provided will be appreciated.

I keep getting 0.0008773 moldm-3... Says I'm wrong.Oddly I find these type of equations extremely simple, but for some reason I can't get this I feel like I'm making a stupid mistake somewhere...
2. (Original post by TonyGuacamole)
I am required to obtain an accurate value of molarity (concentraton) of a given solution of Sodium Hydroxide. The Standardisation is carrid out by titration against a known and accurate weight of the primary standard KHP (Given Mr: 204.22)

Mass of KHP/g = 0.6002
NaOH titre value 1/ml = 29.85 ml

What s the Molarity of the NaOH solution?

Any help provided will be appreciated.

I keep getting 0.0008773 moldm-3... Says I'm wrong.Oddly I find these type of equations extremely simple, but for some reason I can't get this I feel like I'm making a stupid mistake somewhere...
did you write a balanced equation?
did you use mol=mass/mr and n=v*c?
did you convert your units correctly?
3. (Original post by thefatone)
did you write a balanced equation?
did you use mol=mass/mr and n=v*c?
did you convert your units correctly?
KHC8H4O4 + NaOH -----> KNaC8H4O4 + H2O

I worked out the number of moles for KHP which is 0.6002/204.22 = 0.00293899

I assumed this means C= 0.00293899 x (29.85/1000)?

This equals 0.00008773, 0.0001 in 4 decimal places.
4. what volume KHP reacted with 29.85cm^3 of NaOH?

^^ ignore this
5. (Original post by TonyGuacamole)
KHC8H4O4 + NaOH -----> KNaC8H4O4 + H2O

I worked out the number of moles for KHP which is 0.6002/204.22 = 0.00293899

I assumed this means C= 0.00293899 x (29.85/1000)?

This equals 0.00008773, 0.0001 in 4 decimal places.
also c=1000n/v assuming the volume is in cm^3
6. so using c=1000n/v
i got 1000*2.9x10^-3/29.85= 0.098 molarity
7. (Original post by thefatone)
so using c=1000n/v
i got 1000*2.9x10^-3/29.85= 0.098 molarity
Yeah I realised my mistake after a few second after posting this! Thank You anyway )
8. (Original post by thefatone)
so using c=1000n/v
i got 1000*2.9x10^-3/29.85= 0.098 molarity
Also could I ask you another question if you don't mind? It's the same thing but for titre 2. This time the grams are 0.6066.
KHP (Given Mr: 204.22)

Mass of KHP/g = 0.6066
NaOH titre value 1/ml = 29.85 ml

What I'm getting is this:

Moles = 0.6066/204.22
= 0.00297033

Concentration = 0.00297033/0.02985
= 0.09950841
to 4 d.p = 0.0995

Am I wrong? The system is making me final lose marks because of it. Last error was due to a simple calculator mistake, but this time I'M SURE it's correct!
9. (Original post by TonyGuacamole)
Also could I ask you another question if you don't mind? It's the same thing but for titre 2. This time the grams are 0.6066.
KHP (Given Mr: 204.22)

Mass of KHP/g = 0.6066
NaOH titre value 1/ml = 29.85 ml

What I'm getting is this:

Moles = 0.6066/204.22
= 0.00297033

Concentration = 0.00297033/0.02985
= 0.09950841
to 4 d.p = 0.0995

Am I wrong? The system is making me final lose marks because of it. Last error was due to a simple calculator mistake, but this time I'M SURE it's correct!
yes that's exactly what i got too following your calculations. Only thing i see you lose marks for is no units on the concerntration but that's a small thing possibly another balanced equation? but i doubt they'll penalise you for not writing out the equation again
10. (Original post by thefatone)
yes that's exactly what i got too following your calculations. Only thing i see you lose marks for is no units on the concerntration but that's a small thing possibly another balanced equation? but i doubt they'll penalise you for not writing out the equation again
Thank You for your help! It was apparently a system error!

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