Question

16. 3N02(g) + H2O(l) → 2HNO3(aq) + NO(g) a. How many moles of NO are produced from 2.0 moles H20? b. How many grams of NO2 are needed to produce 65g of HNO3? 100

Answer 1

Concepts used to solve:

· To calculate molar mass of a compound, add the atomic masses of each component atom.

· Equ1: No of moles =

Mass of substance(ing) Molar mass inmor

· To find how much substance is produced or consumed, always compare the number of moles from the balanced chemical reaction. (don’t compare masses, or volumes, or concentrations).

16)

Balanced reaction :

3NO2 (g) + H2O (l)   =    2HNO3 (aq) + NO (g)

a.

From the reaction, we see that 1 mole H2O will give 1 mole NO.

So, 2.0 moles H2O will give 2.0 moles of NO.

b.

65g of HNO3 is formed. Molar mass of HNO3 = 63g/mol

Using equ1, no. of moles of HNO3 = = 1.03 moles

65g 63 g/mol

From the balanced equation, 2 moles HNO3 is formed from 3 moles NO2

Thus, 1.03 moles HNO3 is formed from = 1.545 moles NO2.

X 1.03

Mass of NO2 (molar mass = 46g) (using equ1) = 1.545 moles x 46g/mol = 71.07g