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What mass of sodium carbonate would be required to prepare 250 ml of 0.1 M sodium carbonate?
please help and explain it to me, i really dont understand
you have a volume and a concentration so work out the moles n = (C x V)/1000
Then work out the mass m = n x Mr (you know that sodium carbonate is Na2CO3 so use the periodic table to work out the Mr)
(Original post by wag12k12dunkno)
What mass of sodium carbonate would be required to prepare 250 ml of 0.1 M sodium carbonate?
please help and explain it to me, i really dont understand
Okay, so here is how you do it First, you find the moles of sodium carbonate in the given solution. moles=concentraton x volume (n=cv) =0.1mol/dm3 x (250/1000)dm3 (0.1M = 0.1mol/dm3 and converting 250ml into dm3 by dividing by 1000) =0.025mol Next, you find out the molecular mass of Na2CO3= ( 23 x 2) + 12 + (16 x 3) = 46 + 12 + 48 =106 (g/mol) Then, you find out the mass of Na2CO3 needed to give .025 mol (the amount of moles in the solution) moles= mass / molar mass Therefore, mass = moles X molar mass =0.025 x 106 2.65gHope this helps
(Original post by Munrot07) you have a volume and a concentration so work out the moles n = (C x V)/1000
Then work out the mass m = n x Mr (you know that sodium carbonate is NaCO3 so use the periodic table to work out the Mr)
thanks but isnt sodium carbonate na2co3 and so will it be 0.025*106=2.56g! and also can you explain how it all works
(Original post by 4evershinee)
Okay, so here is how you do it
First, you find the moles of sodium carbonate in the given solution.
moles=concentraton x volume (n=cv)
=0.1mol/dm3 x (250/1000)dm3
(0.1M = 0.1mol/dm3 and converting 250ml into dm3 by dividing by 1000)
=0.025mol Next, you find out the molecular mass of Na2CO3=
( 23 x 2) + 12 + (16 x 3)
= 46 + 12 + 48
=106 (g/mol) Then, you find out the mass of Na2CO3 needed to give .025 mol (the amount of moles in the solution)
moles= mass / molar mass
Therefore, mass = moles X molar mass
=0.025 x 106
2.65g
Hope this helps
thanks so much! i just did it before the reply but this was very clear, cheers
(Original post by wag12k12dunkno)
thanks so much! i just did it before the reply but this was very clear, cheers
(Original post by 4evershinee)
No probs
What mass of calcium chloride would be required to prepare 2 litres of 0.5 M calcium chloride So do i find out the moles so (2*0.5)/1000= 0.001 so then moles= mass/molar mass so mass= moles* molar mass molar mass of cacl2 is 111 so 0.001*111= 0.111
i know iv gone wrong somewhere here
(Original post by Munrot07) you have a volume and a concentration so work out the moles n = (C x V)/1000
Then work out the mass m = n x Mr (you know that sodium carbonate is Na2CO3 so use the periodic table to work out the Mr)
please help with next question im not sure where i went wrong i dont know if i had to divide by 1000 or not
(Original post by wag12k12dunkno)
What mass of calcium chloride would be required to prepare 2 litres of 0.5 M calcium chloride So do i find out the moles so (2*0.5)/1000= 0.001 so then moles= mass/molar mass so mass= moles* molar mass molar mass of cacl2 is 111 so 0.001*111= 0.111
i know iv gone wrong somewhere here
Remember that ml=cm3 they're both the same.
(Original post by wag12k12dunkno)
please help with next question im not sure where i went wrong i dont know if i had to divide by 1000 or not
(Original post by cleveradam) convert L to ML = 2L = 2000ML 2000 X 0.5/1000= 1 1 x 111 = 111
Remember that ml=cm3 they're both the same.
why do i have to convert L to ML in the last question i just divided by 1000
(Original post by Munrot07)
you only divide by 1000 if you have cm^3 because you need it in dm^3. If the volume is in dm^3 do not divide by 1000. 1dm^3 = 1 litre
(Original post by Munrot07)
you only divide by 1000 if you have cm^3 because you need it in dm^3. If the volume is in dm^3 do not divide by 1000. 1dm^3 = 1 litre
moles= mass/molar mass dw i was being dumb
(Original post by Munrot07)
you only divide by 1000 if you have cm^3 because you need it in dm^3. If the volume is in dm^3 do not divide by 1000. 1dm^3 = 1 litre
You need to prepare 2.500 L of 1M sodium carbonate. What mass of sodium carbonate is required for this solution?
(Original post by wag12k12dunkno)
thanks so much! i just did it before the reply but this was very clear, cheers
can u fix this one?
(Original post by mrcullen) You need to prepare 2.500 L of 1M sodium carbonate. What mass of sodium carbonate is required for this solution?
can u fix this one?
I just tried many times and I got incorrect the mass for Na2CO3. 105.99 g/moland I got for my question 264.975 g/mol so could check out for me please ?
(Original post by mrcullen) You need to prepare 2.500 L of 1M sodium carbonate. What mass of sodium carbonate is required for this solution?
can u fix this one?
I just tried many times and I got incorrect the mass for Na2CO3. 105.99 g/moland I got for my question 264.975 g/mol so could check out for me please ?