Question

Approximately how much greater in mass is a d2o molecule than an h2o molecule? (assume the oxygen atoms have a mass number of 16. deuterium, d, is an isotope of hydrogen with a mass number of 2, 2h.)

Answer 1

The deuteriuoted water that is $D_{2}O$ consists of an isotope of hydrogen in place of hydrogen from the normal water. The approximate mass of deuteriuoted water and normal water can be calculated as {(2×2)+16} = 20. However the exact mass of $D_{2}O$ is 20.027 g/mole, whereas the mass of water can also be calculated as- {(1×2)+16}=18, however the exact mass of ($H_{2}O$) molecule is 18.015 g/mole. Thus the difference between the mass of the molecules are (20.027 - 18.015) = 2.01 2g/mole.

Answer 2

Answer:

$D_2O$ molecule is greater than $H_2O$ molecule by 2 amu.

Explanation:

Mass of $H_2O$ molecule:

$M_{H_2O}$= 2 × 1 amu + 1 × 16 amu = 18 amu

Mass of $D_2O$ molecule:

$M_{D_2O}$= 2 × 2 amu + 1 × 16 amu = 20 amu

Difference between mass of $D_2O \& H_2O$

$M_{D_2O}-M_{H_2O} =20 amu - 18 amu = 2 amu$

$M_{D_2O} =2+M_{H_2O}$

$D_2O$ molecule is greater than $H_2O$ molecule by 2 amu.