Question

If you have 5 moles of C3H8 and 5 moles of C4H10, which sample has more molecules? Which sample has more mass?

Answer 1

they have an equal number of molecules. a mole is a number of molecules so if there is 5 miles of each then that is the same number of molecules. c4h10 is more massive than c3h8. so 5 miles of c4h10 is more massive than 5 miles of c3h8.

Answer 2

Answer: The mass of butane is more than the mass of propane and both the compounds have same number of molecules.

Step-by-step explanation:

We are given:

Moles of propane = 5 moles

Moles of butane = 5 moles

According to mole concept:

1 mole of a compound contains
`6.022* 10^(23)` number of molecules

So, 5 moles of propane will contain =
`(5* 6.022* 10^(23))=3.011* 10^(24)` number of molecules.

And, 5 moles of butane will contain =
`(5* 6.022* 10^(23))=3.011* 10^(24)` number of molecules.

To calculate the mass for given number of moles, we use the equation:

`\text{Number of moles}=\frac{\text{Given mass}}{\text{Molar mass}}` .....(1)

• For propane:

Moles of propane = 5 moles

Molar mass of propane = 44 g/mol

Putting values in equation 1, we get:

`5mol=\frac{\text{Mass of propane}}{44g/mol}\\\\\text{Mass of propane}=(5mol* 44g/mol)=220g`

• For butane:

Moles of butane = 5 moles

Molar mass of butane = 58 g/mol

Putting values in equation 1, we get:

`5mol=\frac{\text{Mass of butane}}{58g/mol}\\\\\\text{Mass of butane}=(5mol* 58g/mol)=290g`

Mass of butane > Mass of propane

Hence, the mass of butane is more than the mass of propane and both the compounds have same number of molecules.