How many moles are present in 1.25x1023 molecules of salt (NaCl)?

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

aquifers are bounded above and below by impermeable rock. the driving force of groundwater movement in confined aquifers is pressure, rather than gravity.

it is the most commonly accepted one