The chemical equation below shows the decomposition of nitrogen triiodide (ni3) into nitrogen (n2) and iodine (i2). 2ni3 mc030-1.jpg n2 + 3i2 the molar mass of i2 is 253.80 g/mol, and the molar mass of ni3 is 394.71 g/mol. how many moles of i2 will form 3.58 g of ni3?
a) 0.00907
b) 0.00940
c) 0.0136
d) 0.0212

The moles of I2 that will  form 3.85 g of NI3  is 0.0136  moles ( answer c)

   calculation

 2 NI3 → N2  + 3 I2

Step 1: calculate  the moles of NI3  that decomposes

 moles= mass/molar mass

=3.58 g/ 394.71 g/mol = 0.00907 moles

Step 2 :  use the mole ratio of NI3  to I 2  which is 2:3 to  calculate the moles of I2

 = 0.00907  x3/2  =0.0136  moles  ( answer C)