1. Water of crystallization Beāte Laķe Teacher of biology Riga Secondary Night (Shift) School No.14

4. H 2 O crystals

7. In rocks water of crystallization can be found 20 times more than in oceans and sees

8. Crystals that have locked up water in themselves for millions of years..

9. Quartz

10. While distributing water from crystals we can learn about the development of the Earth

11. Crystals of gympsum

12. Stalactites made by water in Slovenia

13. Crystalhydrates Crystal hydrate is a hard crystal matter that has chemicly joined with water - -water of crystallization -water of crystallization (e.g., AlCl 3 ·6H 2 O, BeCl 3 ·4H 2 O etc.). While heating crystalhydrates, water of crystallization can fully or partly be saparated. CuSO 4 · 5H 2 O Crystalhydtare CuSO 4 · 5H 2 O No-water substance CuSO 4 + 5H 2 O Water of crystallization 5H 2 O

14. No-water CuSO 4 when added water– heat is caused to spread– So a chemical reaction is happening.

15. Different colours of crystalhydrates: Cu(NO 3 ) 2 ·6H 2 O blue. CoCl 2 ·6H 2 O red CuSO 4 ·5H 2 O blue. CuSO 4 ·1H 2 O whites. CuSO 4 ·5H2O

16. [Cu(4H 2 O)]SO 4. H 2 O- formula of complex combination.

17. Pink colour of Mn(II) crystalhydrates, e.g., Mn(NO 3 ) 2 ·6H 2 O and MnCl 2 ·2H 2 O MnCl 2 ·2H 2 O Mn(NO 3 ) 2 ·6H 2 O

18. Ni(NO 3 ) 2 x6H 2 O.

19. Gympsum CaSO 4 ·2H 2 O

20. Crystals of gypsum can reach up to 15 m

22. Heated CaSO 4 ·½H 2 O is used in medicine, art, construction.

23. Exercise 74,25 g zinc nitrate’s crystalhydrate consists of 27,00 g of water. Calculate the formula of the crystalhydrate!

24. Clue a) A formula of the unknown crystalhydrate is written as Zn(NO 3 ) 2 ·xH 2 O, where x shows, how many moles of water contains the particular crystalhydrate to each mole of no-water salt. b) Calculate the no-water salt’s mass in the crystalhydrate. m(Zn(NO 3 ) 2 ) = m(Zn(NO 3 ) 2 ·nH 2 O) – m(H 2 O) = 74,25 – 27,00 = 47,25 g

25. Further… c) Calculate the no-water salt’s and water’s amount in the crystalhydrate.

26. Further.. d) To form the formula the crystalhydrate, calculate how many moles of water are joined with one mole of no-water salt. With 0,25 moles Zn(NO 3 ) 2 are joined 1,5 moles of water. With 1 mole Zn(NO 3 ) 2 are joined x moles of water e) Calculate x.

27. Answer. f) Write the formula of the crystalhydrate. Zn(NO 3 ) 2 ·6H 2 O

28. Bibliography Ahmetovs N., “Neorganiskā ķīmija” – R: Zvaigzne, 1978. Feldmanis F., Rudzītis G.,“Neorganiskā ķīmija” – R: Zvaigzne, 1981. Valdis Segliņš Minerāli un ieži.-RaKa, 2007.g. www.google.com www.webelements.com www.webminerals.com