If I am given a solid chemical form of both the acid and the base, how do I determine how many grams of each I need to make 1L of a 25mM Tris-HCl buffer with acid concentration of 18.94mM, and base concentration of 6.06mM?
To determine the amount of the acid and base required to make a 1L buffer with specific concentrations, you need to know the molecular weight of the acid and base.
Here's how you can calculate the required quantities:
1. Determine the moles of acid and base needed:
- Moles of acid (Tris-HCl):
Moles = Concentration (M) x Volume (L)
Moles = 18.94 mM (millimolar) x 1 L = 0.01894 moles
- Moles of base (Tris base):
Moles = Concentration (M) x Volume (L)
Moles = 6.06 mM x 1 L = 0.00606 moles
2. Find the molecular weights of the acid (Tris-HCl) and base (Tris base). Let's assume the molecular weights are:
- Tris-HCl: 157.60 g/mol
- Tris base: 121.14 g/mol
3. Calculate the required grams of each component:
- Grams of acid (Tris-HCl) = Moles x Molecular weight
Grams = 0.01894 moles x 157.60 g/mol = 2.987 grams
- Grams of base (Tris base) = Moles x Molecular weight
Grams = 0.00606 moles x 121.14 g/mol = 0.734 grams
Therefore, you will need approximately 2.987 grams of Tris-HCl acid and 0.734 grams of Tris base to prepare 1L of a 25 mM Tris-HCl buffer with an acid concentration of 18.94 mM and a base concentration of 6.06 mM.