Question

what is the mass of 0.5 mole of water molecules?

Answer 1

9

Explanation:

Given that

Moles of Water = 0.5

We know that Chemical formula for the water is H₂0,

Thus,

Atomic weight of H₂O = (1 ×2) + 16

                                    = 2 + 16

                                    = 18g

Again by formula,

Number of Moles = Mass/Atomic Weight

0.5 = Mass/18

Mass = 18 × 0.5

Mass = 9 g

Thus mass of 0.5 moles of water molecules is 9g

Note:-

Atomic weight of  Hydrogen Molecule = 1

Atomic weight of a oxygen Molecule = 16

Answer 2

Answer:

Explanation:

To Find :-

Mass of 0.5 mole of water molecules.

Formula to be used :-

Number of Moles = Mass/Atomic weight

Solution :-

1 Mole of water (H₂O) = Molecular mass of water

1 Mole of water (H₂O) = Mass of 2H atoms + Mass of O atoms

1 Mole of water (H₂O) = 2 × 1 + 16 = 2 + 16 = 18 g

(Atomic weight of Hydrogen Molecule and oxygen Molecule are 1  and 16)

⇒ Number of Moles = Mass/Atomic weight

⇒  0.5 = Mass/18

⇒ Mass = 18 × 0.5

⇒ Mass = 9 g

Hence, the mass of 0.5 mole of water molecules is 90 g.