Liquids And Solutions

Question 1

What are the two ways to change a substance concentrations

Answer 1

Linear dilutions and log dilutions

Question 2

What’s a linear dilution

Answer 2

Dilutions differ by an equal interval e.g 0.1,0.2,0.3 and so on

Question 3

What’s a log dilution

Answer 3

Dilutions differ by a constant proportion e.g10-1(0.1), 10-2(0.01)

Question 4

What’s a standard curve

Answer 4

Plotting known measurements on a graph to then use to determine unknown values

Question 5

What’s a buffer definition

Answer 5

A solution where adding acids or alkalis have very small effects on the PH. This allows ph in a reaction mixture to be kept constant

Question 6

What are colorimeters used for

Answer 6

To quantify concentration and turbidity

Question 7

How to colorimeters work

Answer 7

Light is split into its component colours and filtered so there is one wavelength of light. This is then passed through the sample solution where a detector picks up absorbable or transmitted

Question 8

What needs to be done before using a colorimeter

Answer 8

They need to be calibrated with an appropriate black sample to provide a baseline reading

Question 9

What’s absorbance used to determine

Answer 9

Concentration of a coloured solution using suitable wavelength filters

Question 10

What’s percentage transmission used to determine

Answer 10

Turbidity such as cells in suspension