ok im not sure how to do this
15.00ml of acetic acid is pipetted into a flask
0.35 grams of sodium acetate trihydrate is added and mixed
then 0.75 of the hydrate is added
1)i assumed that the volume(s) are additions. 15.00ml x .35g *m/1.45g and for the second part 15.00 + 0.35g *mol/1.45 g +0.75 g* mol/1.45g= x
2)not sure how to do the tryhydate. Do i minus it from the total mass of sodium hydrate ? or is it non reactive?
can u show me the proper method to do this ?
I'm not sure what you have done. For example, 0.75 what of the hydrate is added. And the 0.35 g trihydrate are mixed with what? In a separate beaker? With the acetic acid? Please clarify the problem.
Another thing! You haven't asked a question. What are you to calculate?
oh
This is an acid base experiment this is the last stage.
There are two parts:
part 1) 0.3470g sodium acetate trihydate is added to 15.00 ml acetic acid (concentration is 0.20)
then its mixed and a ph is taking--i got 4.30 PH
part II)
Added 0.7618 g of sodium acetate trihydrate to the above mixture. Ph was 4.85
Calculate the Ka for the weak acid.
Not really sure how to do it
HC2H3O2 ==> H^+ + C2H3O2^-
Ka = (H^+)(C2H3O2^-)/(HC2H3O2)
Calculate (H^+) from pH = -log(H^+).
Calculate (C2H3O2^-) from g of the trihydrate. That is moles = grams/molar mass and mole/L (L is 0.15) = M
Calculate (HC2H3O2) from L x M = ?
Plug in and calculate Ka.
For part 2,
determine moles trihydrate added and add that to the amount of trihydrate already there, then total moles/L = M of the (C2H3O2^-). Obtain (H^+) from pH, and (HC2H3O2) is the same as the first part. Calculate Ka.
The correct Ka is about 1.8 x 10^-5.
thanks
i got ka=2.5 x 10^-5 and 2.5 x 10-6
thanks again Jim
here's what i finally ended up with
I don't know why u used 59 grams
nac2h302 x 3h20---> na + c2h302 + 3h20
sodium acetate trihydrate=acetic ions
.3470 g nac2h302 x 3h20 /136.10= 2.550 x 10-3 mol acetic ions formed
2.550 x 10-3 M/.0150 L=.17
ka= (5.0 x 10-5)(.17)/(.20)=4.3 x10-5
part b
1.1088g/136.1=.54
ka =3.8 x10-5
To properly calculate the concentrations of acetic acid and sodium acetate in the solution, you need to follow these steps:
Step 1: Calculate the moles of acetic acid
To find the moles of acetic acid, you can use the equation: Moles = Volume (in liters) x Concentration (in moles per liter).
In this case, the volume is 15.00 ml, which is equal to 0.01500 liters.
To determine the concentration, you'll need additional information, such as the molarity of the acetic acid solution. If you have that information, multiply it by the volume to get the moles of acetic acid.
Step 2: Calculate the moles of sodium acetate trihydrate
To find the moles of sodium acetate trihydrate, you need to know its molar mass. The molar mass of sodium acetate trihydrate is 136.08 g/mol.
Take the given mass of 0.35 grams and divide it by the molar mass to get the moles of sodium acetate trihydrate.
Step 3: Calculate the moles of sodium acetate (hydrate)
Since the sodium acetate trihydrate contains both sodium acetate and water, you need to adjust the calculation by considering the water molecules.
The molar mass of sodium acetate (CH3COONa) is 82.03 g/mol, and the molar mass of water (H2O) is 18.02 g/mol.
Subtract the molar mass of the water molecules (18.02 g/mol x 3 = 54.06 g/mol) from the molar mass of the sodium acetate trihydrate (136.08 g/mol).
So, the molar mass of the sodium acetate (hydrate) is 136.08 g/mol - 54.06 g/mol = 82.02 g/mol.
Now, take the given mass of 0.75 grams and divide it by the molar mass of sodium acetate (hydrate) (82.02 g/mol) to get the moles of sodium acetate.
Once you have calculated the moles for both acetic acid and sodium acetate, you can proceed with any further calculations or analyses dependent on these values. Remember to consider any other factors or variables that may affect the final solution concentration.