If provided with Na acetate and 6.3M acetate acid.decribe how you will prepare 1L of 0.1M acetate buffer pH=5.0[pka=4 acetate acid=4.75,and Na=23,c=12,H=1,O=16]
Well, preparing a buffer is a bit like making a chemistry cocktail! Here's how we can mix up a 1L solution of 0.1M acetate buffer with a pH of 5.0:
1. Calculate the moles of Na acetate required:
- Molarity (M) = (moles of solute) / (volume of solution in liters)
- Moles of solute = Molarity × volume of solution
- We want a 0.1M concentration, so moles of Na acetate = 0.1 × 1 = 0.1 moles
2. Calculate the moles of acetate acid required:
- Since the pKa of acetate acid is 4.75 and we want a pH of 5.0, we can assume equal concentrations of acetate acid and acetate ions (pH = pKa in a buffer).
- Moles of acetate acid = Moles of Na acetate = 0.1 moles
3. Calculate the volume of 6.3M acetate acid needed:
- Molarity (M) = (moles of solute) / (volume of solution in liters)
- Volume of solution = (moles of solute) / (Molarity)
- Volume of 6.3M acetate acid = 0.1 moles / 6.3 M = 0.0159 L or 15.9 mL
4. Add 15.9 mL of 6.3M acetate acid to a container.
5. To make up the rest of the 1 liter solution, add distilled water slowly and swirl gently until the solution reaches the desired volume.
6. Check the pH using a pH meter or indicator paper. If it's not exactly 5.0, you can adjust it by adding a small amount of either acid or base.
Remember, this isn't a precise recipe like baking, but a little bit of chemical wiggle room is allowed. Enjoy your fresh and perfectly pHed acetate buffer!