Chem water

Question 1

Hard water

Answer 1

Water that will not easily form a lather with soap. Cause by magnesium and calcium ions dissolved in water

Question 2

Temporary hardness

Answer 2

Hardness that can be removed by boiling the water

Question 3

Complexometric titration

Answer 3

Titrations involving the formation of a complex between metal ions and a reagent such as edta the end point is marked by a sharp decrease in the concentration of free metal ions

Question 4

Permanent hardness

Answer 4

Hardness that cannot be removed by boiling water

Question 5

Buffer soloution

Answer 5

Solution that resists changing pH ie keep the pH constant

Question 6

Flocculation

Answer 6

Is the coagulating of small suspended particles in water

Question 7

Flocculating agent

Answer 7

Chemical added to water to coagulate suspended particles

Question 8

Biochemical oxygen demand

Answer 8

The amount of dissolved oxygen consumed by biochemical action when a sample of water is kept at 20 degrees c in the dark for 5 days

Question 9

Eutrification

Answer 9

Is the enrichment of water with nutrients leading to excessive growth of algae and other plants

Question 10

Primary treatment of sewage

Answer 10

Mechanical process in which large solids are removed by screening and some suspended solids are removed by sedimentation

Question 11

Secondary treatment of sewage

Answer 11

Biological oxidation process in which The levels of suspended and dissolved organic materials are reduced the sewage is decomposed by means of bacteria which use the nutrients from the sewage together with the oxygen from the air to break down the sewage

Question 12

Tertiary treatment of sewage

Answer 12

Removal of phosphorus compounds by precipitation and the removal of nitrogen compound by biological and ion exchange methods

Question 13

Principle of colorimeter

Answer 13

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