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.

i think it is true since you can test the answer and can use observations to complete it.