1.1b liquids and solutions

Question 1

What is a linear dilution series?

Answer 1

they differ by an equal interval
ex:
0.1, 0.2, 0.3 and so on

Question 2

What is a log dilution series?

Answer 2

they differ by s constant proportion
ex:
10^-1, 10^-2, 10^-3 and so on

Question 3

How would you produce a standard curve and why?

Answer 3

• plotting measured values for known concentrations to produce a line or curve
• allows the concentration of an unknown to be determines from the standard curve

Question 4

How does a buffer work to control pH?

Answer 4

Addition of an acid or alkali has very small effects on the pH of a buffer, allowing the pH of a reaction mixture to be kept constant

Question 5

How do you carry our colorimetry?

Answer 5

• calibration with appropriate blank as baseline
• use the absorbance to determine the concentration of a coloured solution using suitable wavelength filters
• use percentage transmission to determine turbidity, such as cells in suspension