Question

What is the molecular mass of gold, Au?

Answer
What is the molecular mass of gold, Au?

Question at position 11
11

Numeric
6.6 points



Question at position 11
What is the molecular mass of ammonium phosphate, (NH4)3PO4? Round your answer to the second decimal place.

Answer
What is the molecular mass of ammonium phosphate, (NH4)3PO4? Round your answer to the second decimal place.

Question at position 12
12

Numeric
6.6 points



Question at position 12
What is the molecular mass of lead(II) nitrate, Pb(NO3)2? Round your answer to the second decimal place.
Answer
What is the molecular mass of lead(II) nitrate, Pb(NO3)2? Round your answer to the second decimal place.
Question at position 13
13

Numeric
6.6 points



Question at position 13
What is the molecular mass of sucrose, C12H22O11?

Answer

Answer 1

I'll state the atomic masses used (common tabulated values) and show the calculations.

Atomic weights used: H = 1.008, C = 12.01, N = 14.01, O = 16.00, P = 30.97, Pb = 207.2, Au = 196.97 (all in g·mol⁻¹).

1) Gold, Au (atomic mass): 196.97 g·mol⁻¹

2) Ammonium phosphate, (NH4)3PO4:
- NH4 = 14.01 + 4(1.008) = 18.042 → 3 × 18.042 = 54.126
- PO4 = 30.97 + 4(16.00) = 94.97
- Total = 54.126 + 94.97 = 149.096 → 149.10 g·mol⁻¹ (rounded to 2 d.p.)

3) Lead(II) nitrate, Pb(NO3)2:
- NO3 = 14.01 + 3(16.00) = 62.01 → 2 × 62.01 = 124.02
- Pb = 207.2
- Total = 207.2 + 124.02 = 331.22 g·mol⁻¹ (to 2 d.p.)

4) Sucrose, C12H22O11:
- C12 = 12 × 12.01 = 144.12
- H22 = 22 × 1.008 = 22.176
- O11 = 11 × 16.00 = 176.00
- Total = 144.12 + 22.176 + 176.00 = 342.296 → 342.30 g·mol⁻¹

If you prefer I can recalc using more precise atomic weights (IUPAC standard values).