1b- Liquids and Solutions

Question 1

What is characteristic of a linear dilution series?

Answer 1

Dilutions differ by an equal interval, e.g. 0.1, 0.2, 0.3 etc

Question 2

What is characteristic of a log dilution series?

Answer 2

Dilutions differ by a constant proportion, e.g. 0.1, 0.01, 0.001 etc

Question 3

How can unknown concentrations be found?

Answer 3

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

Question 4

What is a buffer used for?

Answer 4

To maintain a constant pH of a reaction mixture (addition of acid or alkali will have very small effects on the pH of a buffer)

Question 5

What must a calorimeter be calibrated with?

Answer 5

A blank so as to obtain a baseline

Question 6

How can the concentration of a coloured substance be determined?

Answer 6

By obtaining an absorbance reading on a colorimeter using suitable wavelength filters

Question 7

Percentage transmission of a sample can be used to determine what and when could this be used?

Answer 7

Turbidity of a sample and this method could be used when calculating the cells in a suspension