If two moles of
chlorine gas reacts
with potassium iodide,
how many grams of
potassium chloride are
produced?

                      298.2 g of KCl

Explanation:

                    The balance chemical equation for given single replacement reaction is as follow;

                                      2 KI + Cl₂ → 2 KCl + I₂

Step 1: Calculate moles of KI produced:

According to balance equation,

                     1 mole of Cl₂ produced  =  2 moles of KCl

So,

                 2 moles of HCl will produce  =  X moles of KCl

Solving for X,

                     X  =  2 mol × 2 mol / 1 mol

                     X  =  4 moles of KCl

Step 2: Calculate Mass of KCl as;

                      Mass  =  Moles × M.Mass

                      Mass  =  4 mol × 74.55 g/mol

                      Mass  =  298.2 g of KCl

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.