If 81g of water is measured out, how many moles are in the sample? * A. 4
B. 5
C. 2.5
D. 4.5

D

Explanation:

because moles = mass /mr

so 81/18(mr of H2O=2+16)

moles =4.5

hope this helps:)

if two electrons have the same n, the same ℓ, and the same ml, then they are in the same orbital. the pauli exclusion principle states that no two identical fermions (a fancy word for electrons and other subatomic particles like electrons) may occupy the same quantum state in an atom simultaneously.

frequency, z, and the collision density, z, in carbon dioxide (co2), r 180 pm at 30 °c and 120 kpa