Question

During the rGFP purification experiment, the instructor will have to make breaking buffer for the students to use. This buffer contains 150mM NaCl. Given a bottle of crystalline NaCl (M.W. = 40g/mole), describe how you would make 500ml of 150mM NaCl. Include the type and sizes of any measuring vessels that you use to make the solution.

Answer 1

dealing with a buffer

use the formula C = n/V...........1

therefore say n = m/Mr.........2

then substitute equation 2 into equation 1

∴ CV = m/Mr

then m = CVMr

Since we are looking for mass of Nacl to make a buffer solution.

m = 150×
`10^(-3)` m
`l^(-1)` × 500×
`10^(-3)` l × 40 g/mol

mass of Nacl = 3g

Explanation: You first weight out 3g of 150mM of NaCl and then dissolve it into a 1000ml beaker dilute it using a volume of 500ml of water to make volume.