Question

The reaction between nitric oxide (NO) and oxygen to form nitrogen dioxide (NO₂) is a key step in photochemical smog formation.

2 NO(g) + O₂(g) → 2 NO₂(g)

How many grams of NO₂ are formed by the complete reaction of 3.04 g of NO?

Answer 1

4.66 g NO₂

Step-by-step explanation:

To calculate the mass of NO₂ formed, you need to

(1) convert grams NO to moles (using the molar mass of NO)

(2) convert moles NO to moles NO₂ (using the mole-to-mole ratio from the balanced equation)

(3) convert moles NO₂ to grams (using the molar mass of NO₂)

It is important to arrange the ratios/conversions in a way that allows for the cancellation of units. The final answer should have 3 sig figs like the given value. (3.04 = 3 sig figs).

Molar Mass (NO): 14.007 g/mol + 15.999 g/mol = 30.006 g/mol

Molar Mass (NO₂): 14.007 g/mol + 2(15.999 g/mol) = 46.005 g/mol

2 NO(g) + O₂(g) -----> 2 NO₂(g)
^ ^

3.04 g NO 1 mole NO 2 moles NO₂ 46.005 g
------------------ x ------------------- x ----------------------- x -------------------- =
30.006 g 2 moles NO 1 mole NO₂

= 4.66 g NO₂