Chapter 15 and 16 Solutions

Chapter 15 and 16 – Solutions

Reading a Solubility Graph

Axes and Locations:

X Axis

Y Axis

How to Use the Graph

Solute –

What is the solute on the graph?

Solvent –

What is the solvent on the graph?

Saturated Solution –

How to find a saturated solution on the graph:

Unsaturated Solution –

How to find an unsaturated solution on the graph:

Supersaturated Solution –

How to find a supersaturated solution on the graph: Solutions Everywhere

Using the three general phases of matter – solid, liquid, and gas – you can come up with nine different types of solutions. Listed below are the nine possible combinations of solutes and solvents. Under each combination, give an example of this type of solution. Then, in the next two columns, describe the specific solute and solvent that make up the solution. Look around for examples… there are solutions everywhere!

Type of Solution Specific Solute Specific Solvent

Gas in Gas ______

Gas in Liquid ______

Gas in Solid ______

Liquid in Gas ______

Liquid in Liquid ______

Liquid in Solid ______

Solid in Gas ______

Solid in Liquid ______Molarity

Solve the problems below:

Molarity = Moles of Solute Liter of Solution

1. What is the molarity of a solution in which 58.0 grams of NaCl are dissolved in 1.0L of solution?

2. What is the molarity of a solution in which 10.0 grams of AgNO3 is dissolved in 500.00mL of solution?

3. How many grams of KNO3 should be used to prepare 2.00L of a 0.500M solution?

4. To what volume should 5.00 grams of KCl be diluted in order to prepare a 0.25M solution?

5. How many grams of CuSO4 5H2O are needed to prepare 100.00mL of a 0.10M solution?

Molality

Solve the problems below:

Molality = Moles of solute Kg of solvent

1. What is the molality of a solution in which 3.0 moles of NaCl is dissolved in 1.5kg of water?

2. What is the molality of a solution in which 25 grams of NaCl is dissolved in 2.0kg of water?

3. What is the molality of a solution in which 15.0 grams of I2 is dissolved in 500 grams of water?

4. How many grams of I2 should be added to 750 grams of CCl4 to prepare a 0.020m solution? 5. How much water is need to dissolve 5.00 grams of KCl in order to prepare a 0.500m solution?

Molarity by Dilution

Acids are usually acquired from chemical supply houses in concentrated form. These acids are diluted to the desired concentration by adding water. Since moles of acid before dilution equal moles of acid after dilution, and moles of acid = M x V, then M1V1 = M2V2.

Solve the following problems:

1. How much concentrated 18.0M sulfuric acid is needed to prepare 250.0mL of a 6.0M solution?

2. How much concentrated 12.0M hydrochloric acid is needed to prepare 100mL of a 2.0M solution?

3. To what volume should 25mL of a 15M nitric acid be diluted to prepare a 3.0M solution? 4. To how much water should 50.0mL of 12.0M hydrochloric acid be added to produce a 4.0M solution?

5. To how much water should 100.0mL of 18.0M sulfuric acid be added to prepare a 1.5M solution?

Molarity Problems

Solve the following problems. In the space below, show a labeled setup. Show any work.

1. What mass of K3PO4 is required to prepare 4.00 liters of a 1.50M solution?

2. What mass of CH3OH is required to prepare 1.50 liters of a 3.00M solution?

3. What volume of a 0.750M solution can be prepared using 90.0 grams of NH4Cl? 4. What is the molarity of a solution that contains 85.0 grams Na2SO4 in 325mL of solution?

5. How many grams of a 0.025M KNO3 solution are needed to prepare 1750mL?

Molarity Problems

The molarity of a solution is the number of moles of solute per liter of solution. The abbreviation for molarity is M. A 3.0M solution of HCl contains 3.0 moles of HCl dissolved in one liter of solution.

1. You are given one liter of a 0.15M solution of Ca(OH)2

A. How many moles of calcium hydroxide are dissolved in one liter of solution?

B. How many grams are dissolved in one liter of solution?

C. How many grams would be dissolved in 0.5 liters of solution?

2. You are given a 0.5M NaI solution A. How many moles are in 500mL of solution?

B. How many grams are in 500mL of solution?

C. How many moles would be in 10.0mL of solution?

3. What is the molarity of a solution containing 4.0 grams of NaOH in one liter?

4. If 4.0 grams of NaOH were dissolved in two liters of solution, what would be the molarity?

Molarity Worksheet

1. How many moles of NaCl are required to make 3.5 liters of a 1.75M solution?

2. What is the molarity of a sugar solution made by adding 6.75 moles of sugar to enough water to make 1.11 liters of solution?

3. How many moles of KNO3 are in 800.0mL of a 0.125M solution? 4. What mass of Na2SO4 is required to make 5.00 liters of a 0.600M solution?

5. What is the molarity of a solution of BaCO3 if 650mL of the solution contains 56.8 grams of barium carbonate?

6. What volume of a 0.350M solution of sugar contains 0.100 moles of sugar?

7. What is the molarity of a solution made by placing 65.8 grams of (NH4)3PO4 in 1560mL of solution?

Solubility

Solubilities of Ionic Compounds Refer to the graph to answer the following questions:

1. Determine the amount of KCl needed to forma saturated solution at 60.0°C.

2. What trend is noticed as temperature increases?

3. If you have 50.0 grams of K2Cr2O7 at 90°C and it is dissolved in a 100 gram sample of water, is the resulting solution saturated, superasaturated, or unsaturated? Explain.

4. What solutes would be supersaturated at 30°C if 40.0 grams were dissolved in a 100.0 gram sample of water?

5. What temperature would create a saturated solution of 30.0 grams of KClO3 in 100 gram sample of water?

Solubilities of Gases Refer to the graph to answer the following questions:

1. What is the solubility trend of gases with increasing temperature?

2. Which gas is most soluble? Use an example and explain.

3. What gas is least soluble? Use an example and explain.

4. At 30°C and standard pressure, how much O2 is soluble?

5. Is 1.0mM of CO soluble of 40°C and standard pressure? Explain.

How Much Solute?

Use the solubility curves on the attached page to answer the following sets of questions:

1. These solubility curves are based on the solubility (in grams) of various salts dissolving in ______grams of water. For all of the salts on the graph, as temperature increases, the solubility ______.

2. a) Which salt is the most soluble at all temperatures? ______

b) Which salt is least soluble at 40°C? ______c) For which salt does the solubility change the least? ______

3. How many grams of each solute below is needed to saturate 100 grams of water at 80°C to prepare the following solutions?

a) K2Cr2O7 ______

b) CuSO4 ______

c) KNO3 ______

d) KCl ______

e) NaCl ______

4. How many grams of each solute below are needed to make a saturated solution at 50°C?

a) KClO3 ______

b) NaNO3 ______

c) NaCl ______

d) KNO3 ______

e) CuSO4 ______

5. The quantity of solute per 100 grams of water used in making some solutions is listed below. Is the solution saturated, unsaturated, or supersaturated?

Solute Temperature (°C) Saturation

20g AgNO3 20 103g NaNO3 60

103g KNO3 60

40g KCl 40

20g KClO3 30

6. At what temperatures are the following solutes equally soluble in 100g of water?

a) NaNO3 and KNO3 ______

b) KNO3 and NaCl ______

c) NaCl and KCl ______

d) CuSO4 and KClO3 ______

e) K2Cr2O7 and NaCl ______

7. How much more solute must be added to keep the following solutions saturated at the temperature changes indicated?

a) NaCl 10°C to 80°C ______

b) NaNO3 20°C to 90°C ______

c) KNO3 50°C to 60°C ______

d) KClO3 20°C to 70°C ______

Molarity Problems

1. Calculate the weight of NaOH needed to prepare 1.0 liters of a 1.5M solution. 2. How many grams of HNO3 are used to prepare 2.00 liters of a 1.25M solution?

3. Calculate the weight of solute required in the preparation of the following: a) 5 liters of a 2.1M NaOH

b) 500mL of a 0.15M NaCl

c) 950mL of a 0.35M H2SO4

d) 3.5 liters of a 4.5M HC2H3O2

e) 1400mL of a 3.5M NaOH

f) 1200mL of a 0.06M KOH

g) 55mL of a 0.166M AgNO3

h) 450mL of a 2.35M Cu(OH)2

4. Calculate the molarity of the following solutions:

a) 1.00 liters which contain 55.0 grams of NaOH b) 5 liters which contain 135 grams of HNO3

c) 500mL which contain 12 grams HNO3

d) 800mL which contain 19.6 grams H2SO4

e) 50mL which contain 3.65g HCl

f) 3kL which contain 2400 grams NaOH

g) 1575mL which contain 1680 grams KOH

h) 1200mL which contain 100.0 grams NaOH

5. 660 grams of HC2H3O2 are available to prepare a 2.5M solution. How many liters of solution can be made?

6. 855 grams of NaOH are used in preparing a 1.55M solution. What volume of solution is made?

7. If 24 liters of a sucrose solution contain 2.736 kg of sucrose, what is the molarity of the solution?

Molarity Problems Calculate the molality of each of these solutions:

1. 3 moles of solute in 1500 grams of water

2. 2 moles of solute in 5000 grams of water

3. 10.5 moles of solute in 3500 grams of water

4. What is the molality of a solution containing 56 grams of KOH in 2000 grams of water?

5. Find the molality of a solution prepared by dissolving 112 grams KOH in 4000 grams of water?

Calculate the molality of these solutions:

6. 60 grams NaOH in 5000 grams of water

7. 20 grams NaOH in 2500 grams of water

8. 30 grams acetic acid, HC2H3O2, in 2000 grams of water

How many grams of solute must be dissolved in: 9. 2000 grams of water to prepare a 3m solution of NaOH

10. 1800 grams of water to prepare a 3m solution of sucrose

11. 500 grams of water to prepare 3m solution of KOH

12. A solution is composed of 30 grams of NaOH in 500 grams of water. What is its molarity? Solutions Practice

1. A solution is prepared by dissolving 17.1 grams of sucrose in 275 grams of water. What is the molality of that solution?

2. Citric acid is one component of soft drinks. What is the molarity of citric acid in 2L of solution made from 150mg if citric acid, C6H8O7?

3. Concentrated sulfuric acid is typically 18.1M H2SO4. Calculate the volume (in mL) of concentrated sulfuric acid needed to prepare 125mL of a 0.100M sulfuric acid solution.

4. In cars, ethylene glycol, C2H6O2, is used as a coolant and antifreeze. If a mechanic fills a radiator with 6.5kg of ethylene glycol and 1.5kg of water, what is the molality of the water?

5. A chemistry student needs 125mL of a 0.150M NaOH solution for her experiment but the only solution available in the laboratory is 3.02M. Describe how the student could prepare the solution she needs.

6. Standard silver nitrate, AgNO3, solutions are used in the titration analysis of samples containing chloride ions. How many grams of silver nitrate are needed to prepare 250.0mL of standard 0.100M silver nitrate solution?

7. If 75.0mL of 0.211M NaOH is diluted to a final volume of 125mL, what is the concentration of NaOH in the diluted solution? 8. A solution made from ethanol, C2H5OH, and water is 1.75m. How many grams of ethanol are contained per 250.0g of water?

Percentage Solution Problems

1. Calculate the weight of NaCl needed to make 670 grams of a 4% solution.

2. How many grams of solute are in 2200 grams of a 7% solution?

3. Calculate the weight of water needed to make 1500 grams of a 5% solution.

4. What weight of a 10% solution can be made by using 1000 grams of water?

5. Alcohol has a density of 0.79g/mL. Calculate the grams of alcohol needed to make 4000 grams of a 1% solution of iodine. Calculate the volume of alcohol that would be needed.

6. When 600 grams of a 3% solution of boric acid are crystallized, what is the weight of acid formed during this process?

7. Calculate the weight of NaOH in 1 liter of a 50% solution. The density of solution is 1.53g/mL. 8. The density of a KOH solution is 1.28g/mL. The solution is 29% solute. How many grams of KOH are in 1 liter of the solution?