12. Calculate the no of molecules in:
34g of ammonia molecules, NH3

1.2 × 10²⁴ molecules NH₃

General Formulas and Concepts:

Chemistry

Explanation:

Step 1: Define

34 grams NH₃

Step 2: Define conversions

Avogadro's Number

Molar Mass of N - 14.01 g/mol

Molar Mass of H - 1.01 g/mol

Molar Mass of NH₃ - 14.01 + 3(1.01) = 17.04 g/mol

Step 3: Convert

= 1.20157 × 10²⁴ molecules NH₃

Step 4: Check

We are given 2 sig figs. Follow sig fig rules.

1.20157 × 10²⁴ molecules NH₃ ≈ 1.2 × 10²⁴ molecules NH₃