Now looking at your third example:
1.00 g of potassium chloride in 0.500 L of solution.
Again, we need to know number of moles and we need to know volume.
We are told we have 1.00 g of potassium chloride. We convert this into moles using the equation:
number of moles = mass in grams / molecular mass.
Molecular mass of potassium chloride = atomic mass potassium + atomic mass chlorine
= 39.0 + 35.5
= 74.5 g/mol
number of moles = 1.00 / 74.5
= 0.0134228
Then, same as in the first example:
Concentration = moles / volume
= 0.0134228/0.5
= 0.0268 M
|