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?
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.
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.
To find the number of moles in a given volume of a substance, you will need to use the formula:
moles = volume (in liters) / molar volume
To find the volume in liters, you need to convert the given milliliters (mL) to liters. Since 1 mL is equal to 0.001 liters, you can convert 5 mL to liters by dividing it by 1000:
5 mL = 5 / 1000 = 0.005 L
Now, to get the number of moles, you need the substance's density and molecular weight. The formula to calculate moles using density and molecular weight is:
moles = mass / molecular weight
First, calculate the mass using the given density. The formula for mass using density is:
mass = density × volume
Given the density, you can calculate the mass:
mass = density × volume = density × 0.005 L
Once you have the mass, divide it by the molecular weight to find the moles:
moles = mass / molecular weight
So, overall, the steps to find the number of moles in 5 mL of a substance given the density and the molecular weight are:
1. Convert the given volume from milliliters to liters by dividing it by 1000.
2. Calculate the mass using the density and converted volume.
3. Divide the mass by the molecular weight to get the number of moles.