1. Iron Decomposition

2. Goals • To determine the ______________________ ________________________________ • To _______________ based on these results • Determine whether __________________ _________________________________________ • Comparison to theoretical %H2O in the hydrate • Observation of litmus during heating • To determine whether a _________________ ______________ occurs by comparing reactions with varying oxidation states

3. Disposal • Iron • Barium & KSCN • KMnO4 • HCl

4. Part 2 • Just like %H2O experiment in CHM161 • Used to determine whether just water is driven off ( or something more • Last time, you determined how much water was lost • This week _________________________________ • So, we determine the ________________________ ____________________, not necessarily the %H2O lost • We compare the ______________to the %H2O in the salt hydrate to determine if something more was lost

5. Part 2 Calculations • %H2O in salt hydrate • Experimental % • Note that mreag – mprod = mlost as gas

6. Are %H2O and % the same?

7. Litmus Tests • What is Litmus Paper? • Blue turns • Red turns • Wet the litmus before sticking it in the vapors • Will the water affect the tests?

8. Litmus Results • What can these tests tell us? • If being in the vapors changes either litmus, ______________________________________ ______________________________________ • If being in the vapors does nothing, __________ _________________________________________ • Check multiple times. Why?

9. Parts 1 & 3 • Part __ is done to compare part __ to • Part __ tests the product from part __ to test hypothesis _________________________ • Try to decide if the part __ tests result in the same changes that you saw for Fe+2 or Fe+3 in part __ • Use the same type of logic as for part __ to base your decisions • In order to do this, must understand experimental controls

10. Experimental Controls • What is a control? • Why do you need them? • What types of controls should you have when you do an experiment?

11. Many types Acts as a catechol + water + apple juice Standard solutions with known concentrations Positive Control

12. Produces _________ that is a result of the _______ _______________________ Can indicate __________ _______________________ _______________________ Can indicate catechol + water Using water to zero a spec Titrating water as a blank (ie Ca-EDTA) Negative Control

13. Today’s Controls (parts 1 & 3) • 1a – control for • 1b – control for • 1c – control for • 1d – control for • 1e – control for • 1f – control for