Introduction to Molarity

Introduction to Molarity
Chemistry 11 Introduction to Molarity Concentration

Discuss with your partner.
What is a solution? What is solute and solvent? What is a strong solution? What is a weak solution?

Discuss with your partner.
How to express strength of solution quantitatively? 1. 2. 3.

New Words Concentrated , dilute

Volume of Solution(in L)
Molarity Concentration Moles of Solute(n) Volume of Solution(in L)

Representative Particles Volume of Gas at STP atomic 1 mole mass Mass 22.4 L Representative Particles Volume of Gas at STP 6.02x10 23 Mole 1 mole 1 mole 22.4 L 6.02x10 23 Mole 1 mole 6.02x10 23 1 mole 22.4 L Density atomic 1 mole mass atomic mass Moles of Solute(n) Volume of Solution(in L) 1 mole Mass Concentration

Concentraiton/Molarity (M)
A concentration that expresses the moles of solute in 1 L of solution Molarity (M) = moles of solute 1 liter solution LecturePLUS Timberlake

LecturePLUS Timberlake
Units of Molarity 2.0 M HCl = moles HCl 1 L HCl solution 6.0 M HCl = moles HCl LecturePLUS Timberlake

The concentration of a solution tells you how much solute that is dissolved in a given amount of solute (water). The molarity is the concentration of a solution. Molarity = Moles Litre moles of NaCl is dissolved in 4.0 L of water, calculate the molarity. Molarity = moles 4.0 L

The concentration of a solution tells you how much solute that is dissolved in a given amount of solute (water). The molarity is the concentration of a solution. Molarity = Moles Litre moles of NaCl is dissolved in 4.0 L of water, calculate the molarity. Molarity = moles 4.0 L = 0.56 moles/litre = 0.56 M (Molar) where M means moles per 1 litre

Molarity Calculation NaOH is used to open stopped sinks, to treat cellulose in the making of nylon, and to remove potato peels commercially. If 4.0 g NaOH are used to make 500. mL of NaOH solution, what is the molarity (M) of the solution? LecturePLUS Timberlake

Representative Particles Volume of Gas at STP atomic 1 mole mass Mass 22.4 L Representative Particles Volume of Gas at STP 6.02x10 23 Mole 1 mole 1 mole 22.4 L 6.02x10 23 Mole 1 mole 6.02x10 23 1 mole 22.4 L Density atomic 1 mole mass atomic mass Moles of Solute(n) Volume of Solution(in L) 1 mole Mass Concentration

Calculating Molarity 1) 4.0 g NaOH x 1 mole NaOH = 0.10 mole NaOH 40.0 g NaOH 2) 500. mL x 1 L _ = L 1000 mL mole NaOH = mole NaOH 0.500 L L = 0.20 M NaOH LecturePLUS Timberlake

2. 5. 00 g KOH is dissolved in 250. mL of water, calculate the
g KOH is dissolved in 250. mL of water, calculate the molarity. Molarity =

g KOH is dissolved in 250. mL of water, calculate the molarity. Molarity = 5.00 g

g KOH is dissolved in 250. mL of water, calculate the molarity. Molarity = 5.00 g x 1 mole 56.11 g

g KOH is dissolved in 250. mL of water, calculate the molarity. Molarity = 5.00 g x 1 mole 56.11 g 0.250 L

g KOH is dissolved in 250. mL of water, calculate the molarity. Molarity = 5.00 g x 1 mole 56.11 g 0.250 L = M

Rearrange concentration/ Molarity formula to find
Moles = ? Volume of Solution = ? Concentration = ?

3. How many moles are there in 205. mL of a 0.172 M solution?

0.205 L x moles 1 L

0.205 L x moles = moles 1 L

4. How many grams NaCl are there in 250.0 mL of 0.500 M solution?

Concentration ----- moles- mass
4. How many grams NaCl are there in mL of M solution? Concentration ----- moles- mass

0.250 L x moles 1 L

0.250 L x moles x g 1 L mole

0.250 L x moles x g = 7.31 g 1 L mole

5. How many grams of NaCl must be used to prepare a 100. 0 mL. of 0
5. How many grams of NaCl must be used to prepare a mL of M solution.

5. How many grams of NaCl must be used to prepare a mL of M solution. L

5. How many grams of NaCl must be used to prepare a mL of M solution. L x moles 1 L

5. How many grams of NaCl must be used to prepare a mL of M solution. L x moles x g 1 L mole

5. How many grams of NaCl must be used to prepare a mL of M solution. L x moles x g = g 1 L mole

6. How many millilitres of a 0. 200 M solution of CoCl2 will
6. How many millilitres of a M solution of CoCl2 will contain 25.0 g?

How many millilitres of a 0. 200 M solution of CoCl2 will. contain 25
How many millilitres of a M solution of CoCl2 will contain 25.0 g? Mass -- moles- volume

6. How many millilitres of a M solution of CoCl2 will contain 25.0 g? 25.0 g

6. How many millilitres of a M solution of CoCl2 will contain 25.0 g? 25.0 g x mole 129.9 g

6. How many millilitres of a M solution of CoCl2 will contain 25.0 g? 25.0 g x mole x 1 L 129.9 g mol

6. How many millilitres of a M solution of CoCl2 will contain 25.0 g? 25.0 g x mole x 1 L x 1000 mL 129.9 g mol L

6. How many millilitres of a M solution of CoCl2 will contain 25.0 g? 25.0 g x mole x 1 L x 1000 mL = mL 129.9 g mol L

Discussion Groups

Discussion Groups Talk about the gift that you would like to have for your next birthday party.

Discuss with your partner
How to express strength of solution quantitatively? What is formula of the concentration What are the different units of concentration, how these units are different from the units of density. What unit of volume should be used in concentration? How to perform calculations if Moles and volume are given to find concentration Mass and volume is given to find concentration Concentration and volume given to find moles Concentration and volume given to find mass

Learning Check M1 A KOH solution with a volume of 400 mL contains 2 mole KOH. What is the molarity of the solution? 1) 8 M 2) 5 M 3) 2 M Drano LecturePLUS Timberlake

Solution M1 A KOH solution with a volume of 400 mL contains 2 moles of KOH. What is the molarity of the solution? 2) 5 M M = 2 mole KOH = 5 M 0.4 L Drano LecturePLUS Timberlake

Learning Check M2 A glucose solution with a volume of 2.0 L contains 72 g glucose (C6H12O6). If glucose has a molar mass of 180. g/mole, what is the molarity of the glucose solution? 1) 0.20 M 2) 5.0 M 3) 36 M LecturePLUS Timberlake

Solution M2 A glucose solution with a volume of 2.0 L contains 72 g glucose (C6H12O6). If glucose has a molar mass of 180. g/mole, what is the molarity of the glucose solution? 1) 72 g x 1 mole x = M 180. g L LecturePLUS Timberlake

Molarity Conversion Factors
A solution is a 3.0 M NaOH.. Write the molarity in the form of conversion factors. 3.0 moles NaOH and L NaOH soln 1 L NaOH soln moles NaOH LecturePLUS Timberlake

Learning Check M3 Stomach acid is a 0.10 M HCl solution. How many moles of HCl are in 1500 mL of stomach acid solution? 1) 15 moles HCl 2) moles HCl 3) moles HCl LecturePLUS Timberlake

Solution M3 3) mL x L = L 1000 mL 1.5 L x mole HCl = 0.15 mole HCl 1 L (Molarity factor) LecturePLUS Timberlake

Learning Check M4 How many grams of KCl are present in 2.5 L of 0.50 M KCl? 1) 1.3 g 2) 5.0 g 3) 93 g LecturePLUS Timberlake

Solution M4 3) 2.5 L x mole x g KCl = 93 g KCl 1 L mole KCl LecturePLUS Timberlake

Learning Check M5 How many milliliters of stomach acid, which is 0.10 M HCl, contain 0.15 mole HCl? 1) 150 mL 2) 1500 mL 3) mL LecturePLUS Timberlake

Solution M5 2) 0.15 mole HCl x 1 L soln x mL 0.10 mole HCl L (Molarity inverted) = 1500 mL HCl LecturePLUS Timberlake

Learning Check M6 How many grams of NaOH are required to prepare 400. mL of 3.0 M NaOH solution? 1) 12 g 2) 48 g 3) 300 g LecturePLUS Timberlake

Solution M6 2) mL x 1 L = L 1000 mL 0.400 L x 3.0 mole NaOH x g NaOH L 1 mole NaOH (molar mass) = 48 g NaOH LecturePLUS Timberlake

Practice from workbook
Page 98 Question 61-64

How to make solutions

How to make solutions Video

How to make solutions 0.15 M NaCl mL solution Calculate moles of solute Calculate mass of the solute from moles Measure mass of the solute using electronic balance Add some water to dissolve the solute Transfer the contents of beaker to volumetric flask Add water to the volumetric flask to mL line Close the volumetric flask Shake the volumetric flask Final solution should be homogeneous

How to make solutions Material: Volumetric Flask Funnel Electronic
Balance Beaker

Learning Check What should be added first to make solution
Solute B. Solvent

Learning Check What will be total volume of 0.25 M of 250mL solution of NaCl? More than 250 mL because addition of solute will increase volume of solution 250 mL Less than 250 mL

Learning Check 3. If you add more solvent than 250 mL then can we remove the solvent from the volumetric flask? a. Yes b. No

Learning Check 4. What kind of container would be best to make solution of accurate concentration? Beaker Volumetric Flask Cylinder

7. Describe how you would prepare 100. 0 mL of a 0. 200 M
7. Describe how you would prepare mL of a M solution of CoCl2. L x moles x g = g 1 L mole Weigh 2.60 g of CoCl2 Dissolve in water Transfer to a 100 mL volumetric flask and fill to the line

What can change concentration of solution?

Adding more solute will concentration. a. Increase b. decrease

Adding more solvent will concentration. a. Increase b. decrease

Discuss with your partner
Summary Discuss with your partner Write 5 things on paper slip that you learned in this lesson

Now exchange your paper slip with next group
Summary Now exchange your paper slip with next group Talk to your partner about 5 things that your next group learned

Assignment Complete assignment 5.6A

Prescription drugs in the correct concentration make you better.
In higher concentration they can kill you.

What steps would you do to make solution?
Group Activity Lab Making Solution Discuss What steps would you do to make solution?

Group Activity 5 students in each group. Make 0.10 M of 100.0 mL
Group number 1 will use NaCl Group number 3 will use NaOH Group number 5 will use BaCl2 Group number 7 will use NaHCO3 Group number 9 will use Cu2SO4 Complete the worksheet.

Introduction to Molarity

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