Question

A glass of water contains 1.2 x 1024 molecules of water. An additional 4.0 moles of water are poured into the glass. How many moles of water are in the glass?

Answer 1

N=1.2·10²⁴
Nₐ=6.0221·10²³ mol⁻¹
n₂(H₂O)=4 mol

n₁(H₂O)=N/Nₐ

n=n₁+n₂=N/Nₐ+n₂

n=1.2·10²⁴/6.0221·10²³ + 4 = 5.99 mol

5.99 moles of water are in the glass