What are the four categories commonly used to classify chemicals and chemical agents in the graphic communications industry

Organic

Plate making

Ink mists

Gas, fumes and dust

Explanation:

the four categories commonly used to classify chemicals and chemical agents in the graphic communications industry are Organic ,Plate making ,Ink mists, Gas, fumes and dust.

Organic refer to those chemicals gotten from living matter and are natural.

Plate making refers to how plates are make and it carry image in the printing process.

Ink mist gotten from ink is use in graphic designs for painting and color indication.

a mercury barometer is a device that uses the physical properties of mercury in a tube to measure barometric pressure. mercury barometers are used for : -

1. measurement of atmospheric pressure  

2. determining the altitude of a place

3. weather forecasting

4. calibration and checking of aneroid barometers

5. application in fluid mechanics

6. measurement of pressure in aircrafts

7. surface weather analysis

8. preparation of barographs

9. usage in physical sciences like physics, astronomy & chemistry

10. preparation of aircraft altimeters

characteristics of mercury barometer : -

1.used to define and measure atmospheric pressure.

2.on the average at sea level the column of mercury rises to a height of about 760 mm.

3.this quantity is equal to 1 atmosphere.

4.it is also known as standard atmospheric pressure.

5.a barometer in which the weight of a column of mercury in a glass tube with a sealed top is balanced against that of the atmosphere pressing on an exposed cistern of mercury at the base of the mercury column, the height of the column varying with atmospheric pressure.