instrumental methods of water analysis

Question 1

what are the 3 methods/instruments used in water analysis?

Answer 1

1. Use of pH meter
2. Atomic absorption spectrometry (AAS)
3. Colorimetry

Question 2

What is a pH meter used to measure?

Answer 2

a pH meter is used in water treatment plants to check the pH of the water

Question 3

What is the pH meter sensitive to?

Answer 3

It is sensitive to hydrogen ion or hydroxide ion concentrations

Question 4

Once the pH meter has measured the pH, what must simply be done?

Answer 4

The pH pf the water can be adjusted as discussed before

Question 5

What happens when the pH sensor is placed in a sample of water?

Answer 5

a voltage is developed between the electrodes in the sensor

Question 6

Is water coming from limestone acidic or basic?

Answer 6

tends to be basic

Question 7

Is water from bogs or sandstone areas acidic or basic?

Answer 7

acidic

Question 8

What does AAS stand for?

Answer 8

atomic absorption spectrometry

Question 9

What does each element have its own of? What can this be used to do?

Answer 9

each element has its own unique absorption spectrum.

This can be used to identify and measure the concentrations of heavy metals present in the water

Question 10

give examples of heavy metals

Answer 10

lead, cadmium, mercury

Question 11

What is the principle of atomic absorption spectrometry? (2)

Answer 11

1. atoms of an element in the ground state absorb light of a particular wavelength that is characteristic of the element
2. the amount of light absorbed is directly proportional to the concentration of the element present in the sample

Question 12

What is colorimetry?

Answer 12

It is a method for measuring the concentration of coloured substances in solution

Question 13

What is the principal of colorimetry?

Answer 13

the amount of light absorbed by a colored solution is proportional to the concentration of the solution

Question 14

define the principle of colorimetry

Answer 14

the principle of colorimetry is that the amount of absorbance of light by a coloured solution is proportional to the concentration of the solution

Question 15

What is done in colorimetry?

Answer 15

white light is passed through a photocell that converts light energy into electrical energy.
the current of electricity is then shown on a meter.
The amount of light that passes through a coloured solution is dependent on the concentration of the solution so its is possible to calculate the concentration of the solution