How many molecules would there be in 1.25 moles of NH3? (Avogadro's number is 6.02 x 10^23 molecules/mol)
A. 6.0 x 10^23
B. 7.5 x 10^23
C. 8.6 x 10^23
D. 1.6 x 10^24
To solve this problem, we need to use Avogadro's number, which tells us the number of molecules in one mole of a substance. We can start by multiplying the number of moles by Avogadro's number:
1.25 moles NH3 x 6.02 x 10^23 molecules/mol = 7.525 x 10^23 molecules
Rounding to two significant figures, we get:
7.5 x 10^23 molecules
Therefore, the answer is B. 7.5 x 10^23 molecules.