 # Precipitation Lab HW 12-12-12! (due 12/13/12)

Here are some hints, reminders and resources for help with tonight's homework!

THE ASSIGNMENT

Choose 3 combinations of chemicals that your team used in lab yesterday that DID have a reaction.  For each, do all of the following:

1. Write the full word equation

2. Write the full chemical equation

3. Write the ionic equation

4. Write the net ionic equation

5. Name the precipitate and its formula

6. Describe what the precipitate looked like

Here is an example of the equations (1-4 in the directions above)

Word equation:  "Aqueous potassium hydroxide and aqueous iron (III) nitrate react to form aqueous potassium nitrate and solid iron (III) hydroxide."

Full chemical equation (use AB + CD --> AD + CB form):

"KOH(aq) + Fe(NO3)3(aq) --> KNO3(aq) + Fe(OH)3(s)"

Note: (aq) and (s) must be correct.  All formulas must be balanced based on ionic charges.

Full Ionic equation (like above but separate ions from aqueous compounds):

"K+(aq) + OH-(aq) + Fe3+(aq) + NO3-(aq) --> K+(aq)  +  NO3-(aq) + Fe(OH)3(s)"

Net Ionic equation (this is like above but does NOT include the spectator ions):

"Fe3+(aq) +  OH-(aq)  --> Fe(OH)3(s)"

Don't forget to name the precipitate and its formula and describe what it looked like!  In the above, the iron (III) hydroxide is the precipitate.  It is a rusty-orange colored solid.  Its formular is Fe(OH)3.

EXTRA HELP!!!!!

For a step by step of how to predict the equations, refer to the video at this link: http://www.kentchemistry.com/links/Kinetics/PredictingDR.htm

For some examples of double displacement reactions (not the ones we did in class), try this. (Do not try these experiments at home!  This demonstrator is definitely a novice; do not rely on his chemistry; video link is only included to show you the color range possible with precipitates.)

For the reaction that I may give a quiz on or have extra credit for in class tomorrow, look at any or all of these:

http://www.youtube.com/watch?v=4NE_a-jFnCM (this one is only 9 seconds long)

Do well!  No excuses!