Warmup (5 minutes) (please draw in lone pairs yourself)

1. Rank these molecules from most(1) to least(5) polar

HO-H

H HH-C-O-C-H H H

H H H H HH-C-C-C-C-C-OH H H H H H

H H O HH-C-C-C-H H H Hn-amyl alcohol

H H H H H H H-C-C-C-C-C-C-H H H H H H H

2. Which compound to the right would be the best solvent for NaCl? Explain.

methanol

H-O-Cl

hexaneisopropyl alcohol

dihydrogen monoxide

1

2

4

35

HH-C-O-H H

Concentration Part 1Percent Composition and

Parts Per MillionGet out your calculator!

1.Which salt solution has the greatest concentration?

[ ] is a measure of the amount of solute in a given amount of solution

Beaker A3 molecules

100 mL solution

Beaker B5 molecules

100 mL solution

Beaker C7 molecules

200 mL solution

2. What is the percent composition of girls and boys in the AP chem class shown?

# Girl students?# Boy students?Total # students?

100 X wholepart

nCompositio %

boys 28.6% 100 X 72

Boys %

girls 71.4% 100 X 75

Girls %

3. A bottle contains 500. mL of water. If this solution has 15.5 mL of pure hydrogen peroxide, what is the concentration of hydrogen peroxide in this solution?

100 X solvent of amount solute of amount

solute of amount nCompositio %

100 X mL 500 mL 15.5

mL 15.5 Peroxide Hydrogen %

3.01% 100 X mL 515.5

mL 15.5 Peroxide Hydrogen %

4. I dilute 10.0 mL of HBr to make a 42.5% HBr solution. What will the total volume of the solution be?

percent composition = amount solute 100 amount solution

42.5 = 10.0 ml 100 x

42.5 x = 10.0 ml (100)

x = 23.5 mlHmmmm…..how much of the solution is just solvent (water)?

______ ___________ 42.5 42.5

5. If a concentrated solution of hydrogen peroxide has a percent composition of 65%, how many mL of pure hydrogen peroxide would be contained in a 0.750 L solution?

percent composition = amount solute 100 amount solution

65 = x_ 100 0.750 L

65 (0.750 L) = x 1000.49 L = x

0.49 L (1000 ml) = 1 L

490 ml

6. What mass (in grams) of NaCl is necessary to make a 5.0% NaCl solution using 82 ml (82 GRAMS) of water? JUST WATER!

percent composition = amount solute 100 amount solution

5.0 = x _ 100 x + 82

5.0 (x + 82) = x (100)

5.0x + 410 = 100x

410 = 95x x = 4.3 grams NaCl

7. For cavity prevention, the recommended concentration of fluoride ions in our drinking water is 0.7 to 1.2 parts per million (ppm). Too much fluoride can result in discolored teeth. If the concentration of F- in Orange County is 0.85 ppm, what mass of fluoride would be contained in a 7.2 gram tap water sample from and OCHSA bathroom?

ppm = amount solute 106 amount solution

0.85 = x grams F-

106 7.2 gram

0.85 (7.2 gram ) = x grams F-

106

6.1 x 10-6 g F-

ppm = amount solute 106 amount solution

8. What is the concentration of mercury (in ppm) if 3 grams mercury is found in a 15 kg sample of ocean water?15 kg (1000g) = 15000 g 1kg

x ppm = 3 g 106 15000 g

x ppm = 3 g (106 ) 15000 g

x = 200 ppm

9. What mass of mercury (in grams) would be contained in a 40.0 kg sample of ocean water at this same concentration?

40.0 kg (1000g) = 4 x 104 g 1kg

ppm = amount solute 106 amount solution

200 ppm = x g Hg 106 4 x 104 g

200 ppm(4 x 104 g) = x = 8 g Hg 106

Análisis químico mg/l (ppm)Calcio 11.9

Magnesio 10.3Hierro menos de 0.1Flúor menos de 0.1

Sodio 7.0pH 6.63

Potasio 4.7Sulfatos 4.0

Dureza del calcio 29.7Dureza del

magnesio 35.7

Alcalinidad total 67.8S.T.D 184

El Agua Cristal es mejor porque ha sido filtrada por la naturaleza durante décadas, adquiriendo de manera natural los minerales necesarios para un perfecto equilibrio del organismo.

La NSF certifica que Agua Cristal cumple con las más estrictas normas de calidad requeridas por la FDA de los Estados Unidos. Un envase de 600 ml contiene: 

Sweet! Concentration Concepts! Work in lab groups Pour ‘solution’ back into ‘original solution’

when you’re done We haven’t done all the concentration

types YET, but you can go back and do those problems later if you can’t figure them out today (formulas are all given)

Don’t eat anything