Iago is of most cunning nature, but it is only by misfortune and circumstance that Cassio and Desdemona fall to his plans. Good luck, write if you need more help.
Here is a compleate run down of the pracs in the topic, starting with what you need.
http://www.boredofstudies.org/courses/science/chemistry/1109495704_2004_Chemistry_Notes_steph@nie.doc
Just as a note, destructive idicators are ones where you add something to the solution, ie universal indicator. A pH meter is nondestructive as the substance can still be used.
In my opionin, I dont believe they would work. Many relationships need the physical contact to survive, and even if there is that set aside time for the couple to see each other, as soon as something comes up the relationship starts to fall apart. But then, if you are dedicated enough and you...
Hey there, Im in year 12 and i do Chemistry. Yes it does have to do with valencies.
Al+0(2)=Al(2)O(3)
then once you balance it its...4Al(2) + 3O(2)---->2Al(2)o(3
Oxygen has a valency of 2-, Aluminium has a valency of 3+, so to balance the valencies ie have no plus or minus' you need 2Al...