Given that 4 nh3 + 5 o2 → 4 no + 6 h2o, when 4.50 mol of h2o are formed, the amount of no formed is 3.00 mol.

We need to examine the balancing coefficients of this equation.
4 NH3 + 5 O2 → 4 NO + 6 H2O

From the above equation, it is clear that the formation of 4 moles of NO is accompanied by the formation of 6 moles of H2O.
This means that the ratio between NO:H2O is 2:3

Based on this, if 4.5 moles of H2O are formed then number of NO moles formed (given the symbol n) will be calculated as:
n = 4.5 x (2/3) = 3 moles (cross multiplication)

1.from liquid state to gaseous state is evaporation 3.solid to liquid is melting 5. solid to gaseous state is sublimation 6. gas to solid state is decomposition 7. a change of state is known as the states of matters