Question

How many moles of Carbon are in 3.06 g of Carbon

Answer 1

`\boxed {\boxed {\sf 0.255 \ mol \ C }}`

Step-by-step explanation:

If we want to convert from grams to moles, the molar mass is used. This is the mass of 1 mole. They are found on the Periodic Table as the atomic masses, but the units are grams per mole (g/mol) instead of atomic mass units (amu).

Look up the molar mass of carbon.

• Carbon (C): 12.011 g/mol

Set up a ratio using the molar mass.

`\frac {12.011 \ g \ C}{ 1 \ mol \ C}`

Since we are converting 3.06 grams to moles, we multiply by that value.

`3.06 \ g \ C*\frac {12.011 \ g \ C}{ 1 \ mol \ C}`

Flip the ratio. This way, the ratio is still equivalent, but the units of grams of carbon cancel.

`3.06 \ g \ C* (1 \ mol \ C)/(12.011 \ g\ C)`

`3.06 * (1 \ mol \ C)/(12.011 )`

`\frac {3.06}{12.011 } \ mol \ C`

`0.25476646 \ mol \ C`

The original measurement of grams (3.06) has 3 significant figures, so our answer must have the same. For the number we calculated, that is the thousandth place.

• 0.25476646

The 7 in the ten-thousandth place tells us to round the 4 up to a 5.

`0.255 \ mol \ C`

3.06 grams of carbon is approximately 0.255 moles of carbon.