Answer:
8.55 × 10²² Molecules
Solution:
Step 1: Calculate the Mass of Water as;
Density = Mass ÷ Volume
Solving for Mass,
Mass = Density × Volume
Putting values,
Mass = 1 g.mL⁻¹ × 2.56 mL
Mass = 2.56 g
Step 2: Calculate Moles of Water as,
Moles = Mass ÷ M.Mass
Putting values,
Moles = 2.56 g ÷ 18 g.mol⁻¹
Moles = 0.142 mol
Step 3: Calculate Number of Molecules of Water as,
# of Molecules = Moles × 6.022 × 10²³
Putting value of mole,
# of Molecules = 0.142 × 6.022 × 10²³
# of Molecules = 8.55 × 10²² Molecules
