Question

Consider separate 100.0 gram samples of each of the following: H2O, N2O, C3H6O2, CO2 Determine which 100.0 gram sample will have the greatest number of oxygen atoms and list them in order from greatest to least.

Answer 1

Answer : The sample
`H_2O` has greatest number of oxygen atoms.

The order of number of oxygen atoms from greatest to least will be:

`H_2O>CO_2>C_3H_6O_2>N_2O`

Explanation :

First we have to calculate the moles of
`H_2O,N_2O,C_3H_6O_2\text{ and }CO_2`

`\text{Moles of }H_2O=\frac{\text{Mass of }H_2O}{\text{Molar mass of }H_2O}`

Molar mass of
`H_2O` = 18 g/mol

`\text{Moles of }H_2O=(100.0g)/(18g/mol)=5.55mol`

and,

`\text{Moles of }N_2O=\frac{\text{Mass of }N_2O}{\text{Molar mass of }N_2O}`

Molar mass of
`N_2O` = 44 g/mol

`\text{Moles of }N_2O=(100.0g)/(44g/mol)=2.27mol`

and,

`\text{Moles of }C_3H_6O_2=\frac{\text{Mass of }C_3H_6O_2}{\text{Molar mass of }C_3H_6O_2}`

Molar mass of
`C_3H_6O_2` = 74 g/mol

`\text{Moles of }C_3H_6O_2=(100.0g)/(74g/mol)=1.35mol`

and,

`\text{Moles of }CO_2=\frac{\text{Mass of }CO_2}{\text{Molar mass of }CO_2}`

Molar mass of
`CO_2` = 44 g/mol

`\text{Moles of }CO_2=(100.0g)/(44g/mol)=2.27mol`

Now we have to calculate the number of oxygen atoms in
`H_2O,N_2O,C_3H_6O_2\text{ and }CO_2`

In
`H_2O` :

As, 1 mole of
`H_2O` contains
`1* 6.023* 10^(23)` number of oxygen atoms

So, 5.55 mole of
`H_2O` contains
`5.55* 6.022* 10^(23)=3.34* 10^(24)` number of oxygen atoms

In
`N_2O` :

As, 1 mole of
`N_2O` contains
`1* 6.023* 10^(23)` number of oxygen atoms

So, 2.27 mole of
`N_2O` contains
`2.27* 6.022* 10^(23)=1.37* 10^(24)` number of oxygen atoms

In
`C_3H_6O_2` :

As, 1 mole of
`C_3H_6O_2` contains
`2* 6.023* 10^(23)` number of oxygen atoms

So, 1.35 mole of
`C_3H_6O_2` contains
`2* 1.35* 6.022* 10^(23)=1.62* 10^(24)` number of oxygen atoms

In
`CO_2` :

As, 1 mole of
`CO_2` contains
`2* 6.023* 10^(23)` number of oxygen atoms

So, 2.27 mole of
`CO_2` contains
`2* 2.27* 6.022* 10^(23)=2.73* 10^(24)` number of oxygen atoms

The order of number of oxygen atoms from greatest to least will be:

`H_2O>CO_2>C_3H_6O_2>N_2O`