Entry Task: April 27th Friday

Question:

What is the molarity of 1.2 moles of calcium carbonate in 1.22 liters of water?

Agenda:

Sign off Discuss Concentration wsNotes on DilutionsHW: Concentration and Dilution ws

1. What is the percent concentration of 75.0 g of ethanol dissolved in 500.0 g of water?

= % NaHCO3

75.0 g ethanol500g water + 75 g ethanol

500g water + 75 g ethanol= 575 g solution

X 10075g NaHCO3

575 g solution= 13.0% ethanol

solution

2. What is the percent concentration of benzene in a solution containing 14.2 grams of benzene in 28.0 grams of carbon tetrachloride?

= % solution14.2 g benzene

28.0 g CCl4+ 14.2 g benzene

28.0 g CCl4+ 14.2 g benzene = 42.2 g solution

X 10014.2g benzene

42.2 g solution= 33.6% solution

3. You have 1500.0 grams of bleach solution. The percent by mass of the solute sodium hypochlorite, NaOCl, is 3.62%. How many grams of NaOCl are in the solution?

= 3.62% NaOClXg NaOCl

1500 g solution

= 3.62 100

Xg NaHCO3

1500 g solution

= 54.3g NaOCl

1500 X 3.2 = 5430 g100

4. What is the percent by volume of ethanol in a solution that contains 35 ml of ethanol in 115 ml of water?

= X% by volume ethanol solution

35 ml of ethanol

35 ml ethanol + 115 ml of water

35 ml ethanol

150 ml solution

= 23.3 %

X 100

5. What is the percent by volume of methanol in a solution that contains 25 ml of methanol in 75 ml of water?

= X% solution25 ml of methanol

25 ml ethanol + 75 ml of water

25 ml ethanol

100 ml solution

= 25.0 %

X 100

6. What is the molarity of an aqueous solution containing 40.0g of glucose (C6H12O6) in 1.5L of solution?

40 g of C6H12O6

180.16 g C6H12O6

1 mole of C6H12O6

0.222 moles of C6H12O6

1.5 L solution

= 0.148 M

7. What is the molarity of a bleach solution containing 9.5 g of NaOCl per liter of bleach?

9.5 g of NaOCl

74.44 g NaOCl

1 mole of NaOCl

0.128 moles of NaOCl 1.0 L solution

= 0.128 M

8. Calculate the molarity of 1.60 L of a solution containing 1.55 g of dissolved KBr.

1.55 g of KBr

119.0 g KBr

1 mole of KBr

0.013 moles of KBr

1.60 L solution

= 0.00814 M

9. Calculate the number of moles of a 125 ml solution (convert to liters) 0.0500M Ba(OH)2.

X moles of Ba(OH)2

0.125 L solution= 0.0500 M

(0.125 L)(0.0500) = 0.00625 moles

10. Calculate the number of grams of a 350 ml solution (convert to liters) 1.50 M Ba(OH)2.

0.525 mol of Ba(OH)2 171.3 g Ba(OH)2

1 mole of Ba(OH)2

X moles of Ba(OH)2

0.350 L solution= 1.50 M

(0.350 L)(1.5) = 0.525 moles Ba(OH)2

89.9 g Ba(OH)2

Dilution is the procedure for preparing a less concentrated solution from a more concentrated solution.

Dilution

Add Solvent

Moles of solutebefore dilution (i)

Moles of soluteafter dilution (f)=

MiVi MfVf=

Dilutions: M1V1 = M2V2

Molarity and Volume of the original solution = Molarity and Volume of the diluted solution.

Make sure the volumes match!!!

Dilutions: M1V1 = M2V2

P1. What volume, in milliliters of 2.00M calcium chloride (CaCl2) stock solution would you use to make 0.50 L of 0.300 M calcium chloride solution? Convert liters to milliliters.

(2.00 M)( X) = (0.300 M )(500 ml)

150 2.00M

= 75 ml

Dilutions: M1V1 = M2V2

P2. What volume of a 3.00M KI solution would you use to make 0.300 L of a 1.25 M KI solution?

(3.00 M)( X) = (1.25 M )(0.300L)

0.375 3.00M

= 0.125 L or 125 ml

Dilutions: M1V1 = M2V2

P3. If I add 25 ml of water to 125 ml of a 0.15 M NaOH solution, what will the molarity of the diluted solution be?

(0.15 M)( 125 ml) = (X M )(150 ml)

18.75 150 ml

= 0.125 M

Use the rest of the period to work on

homework