Last class we learnt about diluting chemicals. It is used often when shipping because it is a lot more cost efficient. If you're wondering how chemicals have anything to do with money, it's because when you dilute something, it's in its simplest form and all the water is removed. Making it a lot lighter and easier to ship. However, even though it is more concentrated, there is still the same amount of moles of the starting solute as there is in the resulting solute. Here's the formula.
M1L1 = M2L2
Ex. Concentrated HCl is 11.6 mol/L. How would you make up 250mL of 0.500 mole/L HCl?
Step 1: Find the number of moles HCl requires.
Moles HCl = 0.500 mole/L HCl x 0.250L
= 0.125 mol HCl
Step 2: Find the volume of 11.6mole/L HCl which contains 0.0625 mol HCl.
Volume required = moles/ molar concentration
= 0.125 mol HCl/ 11.6 mol/L HCl
= 1.08x10^-2 L
No comments:
Post a Comment