Verify by calcula

(a) Mass of given sample = Number of moles × Molar mass

Thus, the mass of 5 moles of CO₂ = 5 × 44 (Molar mass of CO₂ = 44g/mole) = 220 g

The mass of 5 moles of H₂O = 5 × 18 (Molar mass of H₂O = 18g/mole) = 90 g

Therefore, we can say that 5 moles of CO₂ and 5 moles of H₂O do not have the same mass.

(b) Number of moles of given sample:

Thus, the number of moles of 240 g of calcium:

n₁ =

n₁ = 6

The number of moles of 240 g magnesium:

n₂ =

n₂ = 10

Therefore, the ratio of the number of moles: n₁: n₂

6:10

3:5

Now, we can say that 240 g of calcium and 240 g magnesium elements have a mole ratio of 3:5.