Question 9
Mole Concept and StoichiometryHow many molecules are there in 11.2dm3 of ammonia at s.t.p? (G.M.V = 22.4dm3 at stp, NA = 6.02 × 1023mol−1)
- A.3 × 1020
- B.3 × 1021
- C.3 × 1022
- D.3 × 1023
Show the answer and explanation
Answer: D (3 × 1023)
Explanation
Moles = 11.2 ÷ 22.4 = 0.5 mol. Molecules = 0.5 × 6.02 × 1023 ≈ 3 × 1023.