What is the formula weight of ammonium carbonate, (NH4)2CO3?

a) 78.1 amu

b) 96.1 amu

c) 108.4 amu

d) 138.2 amu

To calculate the formula weight of a compound, we need to add up the atomic weights of all the atoms in its chemical formula.

The atomic weights of the elements in ammonium carbonate are:
- Nitrogen (N): 14.01 amu
- Hydrogen (H): 1.01 amu
- Carbon (C): 12.01 amu
- Oxygen (O): 16.00 amu

The formula weight of (NH4)2CO3 can be calculated as follows:
2(NH4) + CO3 = 2(N 14.01 + H 1.01 × 4) + (C 12.01 + O 16.00 × 3)
= 2(14.01 + 4.04) + (12.01 + 48.00)
= 2(18.05) + 60.01
= 36.10 + 60.01
= 96.11 amu

Therefore, the formula weight of ammonium carbonate (NH4)2CO3 is approximately 96.1 amu.

The correct answer is:
b) 96.1 amu