given the balanced equation representing a reaction:

4NH3+5O2-->4NO+6H2O
what is the minimum number of moles of O2 that are needed to completely react with 16 moles of NH3?
(1)16 mol
(2)20.mol
(3)64 mol
(4)80. mol i think its 2 but im not sure.

The answer is 3.0.

16 mol

To determine the minimum number of moles of O2 needed to completely react with 16 moles of NH3, we need to use the mole ratios given in the balanced equation.

The balanced equation shows that for every 4 moles of NH3, we need 5 moles of O2. This can be interpreted as the ratio 4 NH3: 5 O2.

To find the number of moles of O2 needed to react with 16 moles of NH3, we can set up a proportion:

(5 moles O2 / 4 moles NH3) = (x moles O2 / 16 moles NH3)

Cross-multiplying the proportion gives us:

5 moles O2 * 16 moles NH3 = 4 moles NH3 * x moles O2

80 moles NH3 = 4 moles NH3 * x moles O2

Simplifying this equation, we find:

80 moles NH3 = x moles O2

Therefore, the minimum number of moles of O2 needed to completely react with 16 moles of NH3 is 80 mol.

So, the correct answer is (4) 80 mol.

20

4NH3+5O2-->4NO+6H2O

The formula tells us that 4 moles NH3 = 5 moles O2. So use ratio/proportion OR dimensional analysis methods.
16 moles NH3 x (5 moles O2/4 moles NH3) = ??
Note how the unit in the denominator cancels with the unit in the numerator LEAVING the unit (moles O2) you want. If the fraction is placed the other way the units don't cancel.