You need to find the number of moles in 5mL of a substance given the density and the molecular weight.
How do you do this?
chemistry - Chinomso, Thursday, April 15, 2010 at 6:12pm
lets take oxygen to be the substance given. the molecular weight also called the molar mass given as 16. the density always remain constant as 1g/ml. so lets comvert everything together as
5ml*1g/ml*1mole/16g = 0.313moles.
remember that 16g/mol is the molarmass or molecular weight.
chemistry - DrBob222, Thursday, April 15, 2010 at 11:40pm
The infor by chinomso is good except that the molar mass oxygen is 32 and not 16. Let's use something besides oxygen (especially since it doesn't have a density of 1.0 g/mL.)
H2O can be used and it does have a density of 1.0 g/mL.
So 5 mL x (1.0 g/mL) x (1 mol/18 g) = moles H2O where 18 is the molar mass of H2O.