What is the mass, in grams, of 9.10×1024 molecules of methanol (CH3OH)?

Question

What is the mass, in grams, of 9.10×1024 molecules of methanol (CH3OH)?

Answer 1

Hi Nicole,

First convert the number of molecules given to moles, by using Avogadro's number:

1 mole of molecules = 6.022 × 10²³ molecules

The question gave us 9.10 × 10²⁴ molecules so we need to convert that to moles using the relationship in bold above. We will divide by Avogadro's number.

9.10 × 10²⁴ molecules x 1 mol/6.022 × 10²³ molecules = 15.1 moles

We can now convert the number of moles to grams by using the molar mass of methanol (CH₃OH).

To calculate the molar mass, we need the masses from the periodic table:

1C + 4H + 1 O = 32 g...... 32 g of CH₃OH = 1 mole of CH₃OH

We have 15.1 moles, so 15.1 moles × 32g/1 mol = 483 g