1. Warmup 11/19/15 Tell me a story about something that can soak up water Objective Tonight’s Homework To learn how chemicals can absorb and hold water pp 214: 65, 66 pp 215: 67, 68, 69

2. Notes on Hydrates Some chemicals have the ability to soak up and hold water. The water bonds to the chemical structure of the crystal.

3. Notes on Hydrates Some chemicals have the ability to soak up and hold water. The water bonds to the chemical structure of the crystal. We call chemicals that can do this hydrates. Hydrates usually contain a specific ratio of water to chemical.

4. Notes on Hydrates To write a hydrate, we write the chemical name just like regular, but add a dot and the number of water afterwards.

5. Notes on Hydrates To write a hydrate, we write the chemical name just like regular, but add a dot and the number of water afterwards. Example: This is 1 molecule of copper CuSO 4 5H 2 O  sulfate with 5 waters attached to each molecule.

6. Notes on Hydrates To name hydrates, we say the name of the molecule, and add on the type of hydrate. Molecules of waterName 1monohydrate 2dihydrate 3trihydrate 4tetrahydrate 5pentahydrate 6hexahydrate 7heptahydrate 8octahydrate 9nonahydrate 10decahydrate

7. Notes on Hydrates To calculate the number of the hydrate we do the following:

8. Notes on Hydrates To calculate the number of the hydrate we do the following: - Calculate the mass of the compound with water. - Heat it up to drive off all the water. (We call this anhydrous) - Measure the mass again and find the difference.

9. Notes on Hydrates To calculate the number of the hydrate we do the following: - Calculate the mass of the compound with water. - Heat it up to drive off all the water. (We call this anhydrous) - Measure the mass again and find the difference. This difference is the mass of the water. Find the number of the moles of dry material and of the water to find the ratio.

10. Notes on Hydrates Example: What is the formula for a hydrate that is 90.7% SrC 2 O 4 and 9.30% H 2 O? SrC 2 O 4 = 175.62 amu H 2 O = 18.01 amu Next, we treat this like percent composition. 90.7 g * 1 / 175.62 = 0.5163 mol SrC 2 O 4 9.7 g * 1 / 18.01 mol = 0.5385 mol H 2 O Just about the same number, so our ratio is 1:1 So… SrC 2 O 4 ● H 2 O

11. Practice on Hydrates Open your book to page 218 and practice problems 114 and 116. Like usual, the answers will be up front on the desk.

12. Exit Question Name the following hydrate: Mn(NO 3 ) 2 4H 2 O a) Manganese (II) Nitrate tetrahydrate b) Magnesium (II) Nitrate tetrahydrate c) Manganese (II) Nitrate quadrahydrate d) Magnesium (II) Nitrate quadrahydrate e) Manganese (II) Nitrate f) Magnesium (II) Nitrate