Final answer:
The number of particles in 45g of hydrogen fluoride (HF) is 1.355x10^24 particles. The correct answer is option a.
Step-by-step explanation:
The molar mass of hydrogen fluoride (HF) is 20.01 g/mol. To find the number of particles in 45g of HF, we need to calculate the number of moles using the formula:
moles = mass (g) / molar mass (g/mol)
moles = 45g / 20.01 g/mol = 2.249 moles
Since 1 mole of any substance contains 6.02x10^23 particles (Avogadro's number), the number of particles in 45g of HF is:
particles = moles x Avogadro's number
particles = 2.249 moles x 6.02x10^23 particles/mol = 1.355x10^24 particles of HF