Question

Which one has the greatest mass?

1. 3.55 mol O atoms
2. 4.52 g O atoms
3. 0.0032 kg O2 molec
4. 7.39 × 1023 O2 molec

Answer 1

Answer: The correct answer is Option 1.

Step-by-step explanation:

For the given options:

• Option 1: 3.55 mole of O atoms

To calculate the number of moles, we use the equation:

`\text{Number of moles}=\frac{\text{Given mass}}{\text{Molar mass}}`

Moles of Oxygen = 3.55 mol

Molar mass of Oxygen = 16 g/mol

Putting values in above equation, we get:

`3.55=\frac{\text{Mass of oxygen}}{16g/mol}\\\\\text{Mass of oxygen}=56.8g`

Mass of oxygen atoms = 56.8 g

• Option 2: 4.52 g of O atoms

Mass of oxygen atoms = 4.52 g

• Option 3: 0.0032 kg of
  `O_2` molecule

Converting this into grams, we use the conversion factor:

1 kg = 1000 g

So, 0.0032 kg = 3.2 g

Mass of
`O_2` molecule = 3.2 g

• Option 4:
  `7.39* 10^(23)` of
  `O_2` molecule

According to mole concept:

1 mole of an atom contains
`6.022* 10^(23)` number of atoms.

If,
`6.022* 10^(23)` number of atoms occupies 32 grams of oxygen molecule.

So,
`7.39* 10^(23)` number of atoms will occupy =
`(32g)/(6.022* 10^(23))* 7.39* 10^(23)=39.2g`

Mass of
`O_2` molecule = 39.2 g

Hence, the greatest mass is coming out from option 1.

Answer 2

To determine the one with the greatest mass, we convert all options into the same units of mass as follows:

1. 3.55 mol O atoms ( 16 g / mol ) = 56.8 g O
2. 4.52 g O atoms
3. 0.0032 kg O2 molec ( 1000 g / 1kg ) ( 1 mol / 32 g ) ( 2 mol / 1 mol ) ( 16 g / mol) = 3.2 g O
4. 7.39 × 10^23 O2 molec ( 1 mol / 6.022x10^23 molecules) (2 mol / 1 mol)(16 g/mol) = 39.27 g O