Answer:
0.21 mole of NaCl
Explanation:
From the question,
using Avogadro's Constant,
1 mole of every compound contains 6.02×10²³ molecules of that compound.
I.e
1 mole of NaCl ⇒ 6.02×10²³ molecules of NaCl
x moles of NaCl ⇒ 1.25××10²³ molecules of NaCl
Solving for x,
x moles of NaCl = (1 mole of NaCl)×(1.25×10²³ molecules of NaCl)/(6.02×10²³ molecules of NaCl)
x moles of NaCl = (1×1.25×10²³)/6.02×10²³
x = 0.208 mole of NaCl
x ≈ 0.21 mole of NaCl
