Rust (Iron(III) oxide), is produced when metallic iron reacts with oxygen gas in the presence of moisture in the air.

a. Write and balance the equation.

b. how many grams of iron(III) oxide are produced when 120 g iron rusts? 9.675 mol of oxygen gas.

c. If 5.8 L of oxygen gas were present, how many moles of Iron(II) oxide would be produced?

d. If 1.204 x1024 formula units iron(III) oxide of were produced how many liters of oxygen gas would be needed?

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.