pHing

Question 1

how do you calibrate pH meter?

Answer 1

calibration mode, use commercially available solutions for base, acid, and neutral each

Question 2

why do we need buffers?

Answer 2

• Many biological reactions are very pH sensitive, so we need buffer solutions in reaction to maintain a constant pH
• Buffer solutions keep pH in narrow pH range so that the enzymes can work adequately

Question 3

where do we get buffers?

Answer 3

• commercial
• making own

Question 4

how do you calculate how many grams of each component (NaCl and Tris) is added to make Tris buffer?

Answer 4

1. convert given desired final concentration milimolarity (mM) to molarity (M)
2. use M * V = moles with given total buffer volume in L
3. moles = mass (want to find) / molar mass (given)