6 Li + N2 --> 2 Li3N

How much N2 is needed to make 1.34 moles of Li3N?

0.67 moles

Explanation:

6 Li(s) + N2(g) ---> 2 Li3N(s)

The balanced reaction above shows that 6 moles of Lithium, (Li) added to 1 mole of Nitrogen gas, (N2) yields 2 moles of Lithium nitrite, (Li3N)

I.e 1 mole of N2 = 2 moles of Li3N

Since the number of N2 needed to make 1.34 moles of Li3N is unknown, it is represented by Y

So, 1 mole of N2 = 2 moles of Li3N

Y = 1.34 moles of Li3N

To get the value of Y, cross multiply

1.34 x 1 = Y x 2

1.34 = 2Y

To get the value of Y divide both sides by 2

1.34/2 = 2Y/2

0.67 = Y

Thus, 0.67 moles of N2 is needed to make 1.34 moles of Li3N.

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.