2. Separating mixtures and solutions: Evaporation Mixtures and Solutions

3. All water, even rainwater, contains dissolved chemicals called salts. Not all water tastes salty, however.

4. The world’s rivers carry about 4 billion tonnes of dissolved salts to the oceans every year. Salts become concentrated in the oceans because the heat of the Sun causes evaporation of water from the surface, leaving the salts behind.

5. Percentage of salt in some bodies of water Arabian Sea 3.7% Atlantic and Pacific Oceans 3.2–3.7% Baltic Sea 1% Dead Sea 27% Great Salt Lake 5–27% Red Sea 4.1%

6. Evaporation can be used to separate solutions. The solvent evaporates and the solute is left behind.

7. Experiment Put five drops of salt water in a metal spoon. Place the spoon over a candle and evaporate the water and observe what happens.

8. Hi my name’s Walter! Hi my name’s Salty!

9. Salty, don’t talk to those Water particles! Yeah, they think they are so cool ~ covering 70% of the Earth wooo.

10. Yeah, yours is a measly 100 degrees Celsius, ha wimpy! Hey water particles, did you know that our boiling point is 1400 degrees!

11. I think the humans are heating us! Do you feel it getting warmer in here?

12. 100 degrees Celsius … Hey water particles! Where do you think you are going!? HaHa! We are evaporating out of this place!! Have fun in the spoon!!

13. The End Think there’s a chance it will reach 1400 degrees?

14. However, recovering the solvent from the solution is more complicated...

15. Tomorrow - Distillation: separating the parts of a solution glass tubing flask rubber stopper blue liquid hot plate plastic tubing beaker Water Quiz