Wednesday 14 December 2011

Molarity.

Molar concentration is the number of moles of solute in one litre of solution.


Forumla:   Molarity = moles of solute(mol)/ volume of solution(L)

Example: If there is 2.0 of CO2 in 1.0L of solution, what is the molar concentration (molarity)?

M(representing molarity) = 2.0 mol CO2/1.0L
                                      = 2.0M CO2 or 2.0mol/L CO2


For a reaaaally in depth look at molarity check this out!









Monday 12 December 2011

Lab 4C

Today we did a really cool lab. It taught us a lot of things....

First, we had to heat our beakers, just to make sure all of the moisture had been removed. Then we got some hydrate in our crucible. We heated it numerous times, removing all of the water and turning it into a anhydrous salt. We then added a drop of water, changing the colour from white back to the original blue colour. This returned the anhydrous salt to the state of hydrate.
Along the way, we were constantly weighing the substance. From our measurements, we were able to determine the percentage of water in the hydrate, the number of moles of anhydrous salt, the number of moles of water removed from the hydrate and the number of moles of water per mole of the anhydrous salt. Using all of this information, we were able to derive the Empirical Formula of the hydrate.