How many moles of hydrogen would be in 10.0 mL of methanol?

Question

Methanol, CH4O is a liquid at room temperature and its density is 0.792 g/mL 

Answer 1

1.  Find grams of methanol

2.  Find moles of methanol

3.  Find moles of hydrogen

 

1.  Grams of methanol = 10.0 ml x 0.792 g/ml = 7.92 grams

2.  Moles of methanol = 7.92 g x 1 mole/32.0 g = 0.2475 moles

3.  Moles of H = 0.2475 moles methanol x 4 moles "H"/mole of methanol = 0.990 moles of "H"

Answer 2

Hello Destiny

 

We need to first convert volume to mass using the density.

 

d = m/V

 

m = d x V

 

    = 0.792 x 10.0 = 7.92 g

 

Using the molar mass of methanol (32 g/mol), convert grams to moles.

 

7.92 g CH4O x (1 mol CH4O / 32 g CH4O) = 0.248 mol CH4O

 

From the chemical formula of methanol, you can see that in 1 mole of CH4O, there are 4 moles of H atoms.

 

0.248 mol CH4O x (4 mol H / 1 mol CH4O) = 0.992 mol H