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# Dilutions!

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## Dilutions!

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1. Dilutions!

2. Mix 2 solutions together… …they both get diluted. It’s ping pong balls in a bucket…

3. 5 gallon bucket - Ping pong ball

4. 5 gallon empty bucket - 5 Ping pong ball

5. Add 1 gallon of water What’s the “concentration of ping pong balls”? 5 PPB/gallon!

6. Add another gallon of water What’s the “concentration of ping pong balls”? The ping pong balls are no different than atoms or molecules. If you have 5 moles in a bucket, you have 5 moles in a bucket!

7. 5 gallon bucket - Ping pong ball

8. 5 gallon empty bucket Add 5 ping pong balls and 2 baseballs.

9. Add 1 gallon of water What’s the “concentration of ping pong balls”? 5 PPB/gallon! What’s the concentration of baseballs? 5 BB/gallon

10. Add another gallon of water What’s the “concentration of ping pong balls”? The concentration of base balls is:

11. If they are different molecules… The concentration gets calculated separately!

12. Suppose I have 2 Buckets!

13. Add 1 gallon of water 2 BB in 1 gallon of water! 2 BB/gal

14. Add 2 gallon of water 5 PPB in 2 gallons of water 2.5 PPB/gal

15. Suppose I mix the two bukets 2 gallons + 1 gallon = 3 total gallons. The number of objects is unchanged.

16. And what if the objects are the same? They just add together!

17. Add 2 gallon of water 5 PPB in 2 gallons of water 2.5 PPB/gal

18. Add 2 gallon of water 3 PPB in 2 gallons of water 1.5 PPB/gal

19. Suppose I mix the two bukets 2 gallons + 1 gallon = 3 total gallons of “solvent”. The number of ping pong balls also adds: 5 PPB + 3 PPB = 8 total PPB

20. Same with chemical solutions… EXCEPT it’s usually Liters (or mL) of solvent… And it is MOLES! MOLES! MOLES! of solute

21. I mix 250 mL of 0.250 M NaCl with 500 mL of 0.100 M HCl. What is the concentration of NaCl? 0.250 M x 0.250 L = 0.0625 molNaCl The problem doesn’t ask about HCl, but it is the same issue – dilution: 0.100 M x 0.500 L = 0.05 molHCl

22. I mix 250 mL of 0.250 M NaCl with 500 mL of 0.100 M NaCl. What is the concentration of NaCl? 0.250 M x 0.250 L = 0.0625 molNaCl 0.100 M x 0.500 L = 0.05 molNaCl

23. PING PONG BALLS IN A BUCKET!