Plan how you would make 100mL of a buffer solution with a pH of 10.80 to be made using only sodium carbonate, sodium hydrogen carbonate and water.

You should specify the amount of sodium carbonate and sodium hydrogen carbonate that you would use.

Below is what i got up to then im not sure how to find the amount of each

pH = pk2 + log(base/acid)
10.80 = 10.33 + log B/A
B/A = 2.95
CO3^2- = 2.95*HCO3^-

thx

I didn't check any of your calculations. There is no indication of what concentration they want the buffer; therefore, I would assume some convenient (and reasonable) amount of one of the salts, say Na2CO3 = 0.05 mols (which would make the Na2CO3 about 0.5M).

That will be 0.05 x 106 = about 5 g Na2CO3 and 0.05/2.95 = about 0.02 mols (0.2M) NaHCO3 or about 0.02 x 84 = about 1.5 g NaHCO3. First you need to calculate these with a little better accuracy, then plug each into the HH equation and see if you end up with a pH of 10.80.
There is another way to do it; i.e., assume that the concentration of the buffer is to be 0.1M which give you a second equation.
eqn 1 is base = 2.95*acid
acid + base = 0.1
Solve the two equation simultaneously to get acid and base, then convert those to grams. You won't get the same answer from these two calculations because the first one works out to be about 0.7M and the last one we start with 0.1M. I would recommend the latter because 0.7M sounds high to me for making a buffer solution.

To make a buffer solution with a pH of 10.80 using only sodium carbonate (Na2CO3), sodium hydrogen carbonate (NaHCO3), and water, you need to find the appropriate amounts of these components.

1. Start by calculating the concentration ratio (B/A) between the carbonate ion (CO3^2-) and the hydrogen carbonate ion (HCO3^-). You have already done this and found B/A to be 2.95.

2. Since we want to make a 100 mL buffer solution, we can assume the final volume will be 100 mL.

3. Let's assume x represents the amount of sodium carbonate (Na2CO3) in moles and y represents the amount of sodium hydrogen carbonate (NaHCO3) in moles.

4. Since the concentration of CO3^2- is 2.95 times the concentration of HCO3^-, we can say that the moles of Na2CO3 (x) are 2.95 times the moles of NaHCO3 (y).

x = 2.95y

5. To find the amount of each component in grams, you need to multiply the amount in moles by their respective molar masses.

Mass of Na2CO3 = x * molar mass of Na2CO3
Mass of NaHCO3 = y * molar mass of NaHCO3

6. Now, you need to calculate the concentration of each component in the buffer solution.

Concentration of Na2CO3 = (x / 0.1) moles per liter (since the final volume is 100 mL or 0.1 L)
Concentration of NaHCO3 = (y / 0.1) moles per liter

7. Use the Henderson-Hasselbalch equation to find the pH of the buffer solution. However, since we know the desired pH is 10.80, we can skip this step.

8. Finally, substitute the value of y from step 4 into step 6 to find the amount of NaHCO3, and then substitute the value of x into step 5 to find the amount of Na2CO3.

Keep in mind that the molar masses of Na2CO3 and NaHCO3 and the volume (100 mL) are needed to determine the exact amounts.