8.0 dm of NO is mixed with 6.0 dm3 of O, at room temperature and pressure (RTP). The reaction below takes place until one of the reactants is used up.

2NO(g) + O2(g) + 2NO,(9)

What is the volume of the mixture at RTP after the reaction has taken place?

A)8.0 dm3

B)10.0 dm3

C)12.0 dm3

D)14.0 dm3

The volume of the mixture after the reaction is  10 dm³

The correct answer to the question is Option B. 10 dm³

The above is simply a demonstration of Gay-Lussac' law. The volume of the mixture after the reaction can be obtained as follow:

                            2NO(g) + O₂ —> 2NO(g)

Combining Vol:   2 dm³  :  1 dm³   :  2 dm³

Before reaction:  8 dm³  :  6 dm³  :  0

During reaction:  8 dm³  :  4 dm³  :  8 dm³

After reaction:    0 dm³  :  2 dm³ :  8 dm³

The Volume after the reaction = 2 + 8 = 10 dm³

Learn more about Gay-Lussac's law:

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B)10.0 dm3

Explanation:

Now we have to apply Gay-Lussac's law which states that gases combine in simple volumes provided the temperature and pressure remain constant.

                                               2NO(g) + O2(g) >2NO

combining volumes                2            :   1               :  2

Volumes before reaction       8.0            6.0               0.0

Reacting volumes                   8.0            4.0                8.0

Volumes after reaction           -                 2.0              8.0

Therefore;

Total volume after reaction = 2.0 + 8.0 = 10.0 dm^3

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.