MOLARITYA measurement of the concentration of a solution

Molarity (M) is equal to the moles of solute (n) per liter of solution M = n / V = mol / L

2. Calculate the molarity of a solution 2. Calculate the molarity of a solution prepared by mixing 23.0 g of NaCl in prepared by mixing 23.0 g of NaCl in 500.0 mL of water.500.0 mL of water.

1. Calculate the moles necessary to make 50.0 mL of a 3.0 M solution of hydrochloric acid.

3. How many grams of sodium sulfate will be required to make 150.0 mL of a 0.25 M solution?

MOLARITY & DILUTIONM1V1 = M2V2

The act of diluting a

solution is to simply add more

water (or solvent) thus leaving the

amount of solute unchanged.

Q. Calculate the concentration of a NaCl solution made by diluting 20.0 mL of 2.55 M with 235.0 mL of water.

MOLARITY & StoichiometryIn the past chapters, you measured out a solid reactant In the past chapters, you measured out a solid reactant and needed to predict the mass of the product. You and needed to predict the mass of the product. You learned to use the molar mass and mole ratio to achieve learned to use the molar mass and mole ratio to achieve that goal. The same reasoning applies with solution that goal. The same reasoning applies with solution chemistry but instead to using the molar mass you will chemistry but instead to using the molar mass you will use the molarity to convert to moles.use the molarity to convert to moles.

Use the m o le ratiofro m th e b alan ced eq u atio n

u seM o larity

o f A

Use M o lar

m ass o f A

Use M o lar

m ass o f B

u seM o larityo f B

Volum e of A m a ss of A

m oles of A

Volum e of B m a ss of B

m oles of B

Stoichiometry Flow chart

Solution Stoichiometry

MOLARITY & Stoichiometry1.1. How much calcium carbonate will be How much calcium carbonate will be

precipitated by adding 40.0 mL precipitated by adding 40.0 mL calcium chloride to 35.0 mL of 2.55 M calcium chloride to 35.0 mL of 2.55 M potassium carbonate?potassium carbonate?

2.2. What is the concentration of 50.0 mL What is the concentration of 50.0 mL of hydrochloric acid needed to of hydrochloric acid needed to completely react with 9.55 g of completely react with 9.55 g of magnesium metal?magnesium metal?

PRACTICE PROBLEMS #37a_________1. What is the concentration of 250.0 mL of 0.60 moles of HCl?

_________ 2. What volume of 0.7690 M LiOH will contain 55.3 g of LiOH?

_________ 3. How many liters of water must be added to 100.0 mL of 4.50 M HBr to make a solution that is 0.250 M HCl? _________ 4. How many grams of barium sulfate that will precipitate when 500.0 mL of 0.340 M BaCl2 and 300.0 mL of 1.70 M Na2SO4 are mixed?

5. How would you prepare 850.0 mL of a 0.020 M ferric chloride solution if you start with crystals of FeCl3 . 6H2O?

2.4 M2.4 M

3.00 L3.00 L

1.80 L1.80 L

39.6 g39.6 g

Weigh out 4.59 g of the hydrated salt to a graduated cylinder with 800.0 mL then add enough DI water to make 850 mL exactly.

PRACTICE PROBLEM #37b1. What is the concentration of 35.0 mL of 0. 0556 moles of KCl?

2. How many grams of KCl is needed to prepare 50.0 mL of a 0.10 M solution?

3. How many milliliters of water must be added to 30.0 mL of 9.0 M KCl to make a solution that is 0.50 M KCl? 4. How many grams of calcium carbonate will precipitate when 500.0 mL of 0.340 M CaCl2 and 300.0 mL of 1.70 M Na2CO3 are mixed?

5. What is the concentration of the product solution (assuming the volumes are additive) when 500.0 mL of 0.340 M CaCl2 and 300.0 mL of 1.70 M Na2CO3 are mixed?

1.59 M

0.38 g

510 mL

17.0 g

0.425 M

GROUP STUDY PROBLEM #37a______1. How many grams of K3PO4 is needed to prepare 500.0 mL

of a 0.00567 M solution?

______2. What volume of 0.7690 M LiOH will contain 55.3 g of LiOH?

______3. How many milliliters of water must be added to 600.0 mL of 3.40 M HCl to make a solution that is 0.500 M HCl?

______ 4. What is the concentration of the product solution (assuming the volumes are additive) when 24.9 mL of 0.70 M BaCl2 and 45.0 mL of 0.15 M Na3PO4 are mixed?

GROUP STUDY PROBLEM #37b

______1. What is the concentration of 250.0 mL of 0.60 moles of NaOH?

______2. What mass of MgCl2 will be required to prepare 500 mL of 0.150 M solution? ______3. How many milliliters of water must be added to 50.0 mL of 1.97 M NaOH to make a solution that is 0.025 M NaOH?

______ 4. How many grams of barium sulfate that will precipitate when 500.0 mL of 0.340 M BaCl2 and 300.0 mL of 1.70 M Na2SO4 are mixed?

______ 5. What is the concentration of the product solution (assuming the volumes are additive) when 500.0 mL of 0.340 M BaCl2 and 300.0 mL of 1.70 M Na2SO4 are mixed?