22

Section One: How Solutions Form
 * //Chapter 22: Solutions//**

Vocabulary: solution: mixture that has the same composition, color, density, and even taste throughout solute: substance being dissolved solvent: substance doing the dissolving polar: molecules that have a positive area and a negative area

Picture Questions: none

Reading Check: 1. The smaller one is usually the solute. 2. The negative ends of water are attracted to the sugar.

Section Review:

1. List possible ways that phases of matter could combine to form a solution. solid in liquid liquid in liquid solid in solid gas in gas

2. Describe how temperature affects the rate of dissolving. The temperature increase makes the particle movement go up causing more solvent particles to bump into one another. Then the solute particles break loose and dissolve faster.

3. Describe how the metal atoms in an alloy are mixed. The solids are melted so the atoms can be evenly distributed and then formed back into solids.

4. Think critically. Amalgrams, which are sometimes used in tooth fillings, are alloys of mercury with other metals. Is an amalgram a solution? Explain. Yes, because they are alloys and alloys are solutions.

5. Applying math. Find surface area. Calculate the surface area of a rectangular solid with dimensions l = 2 cm, w = 1 cm, and h = 0.5 cm. 9cm (squared)

6. Calculate percent increase. If the length of the rectangle in question 5 is increased by 10%, by how much will the surface area increase? .8cm (squared)

Applying Math: 1. 250cm (squared) 2. 50cm (squared)

Section Two: Solubility and Concentration

Vocabulary: solubility: maximum amount of a solute that can be dissolved in a given amount of solvent at a given temperature saturated solution: solution that contains all the solute it can hold at a given temperature unsaturated solution: any solution that can dissolve more solute at a given temperature supersaturated solution: solution that contains more solute than a saturated solution at the same temperature

Picture Questions: 1. A supersaturated solution is unstable because is contains more solute than a saturated solution.

Reading Check: 1. Solubility is the maximum amount of a solute that can be dissolved in a given amount of solvent at a given temperature. 2. If a saturated solution is heated it becomes an unsaturated solution.

Section Review:

1. Explain. Do all solutes dissolve to the same extent in the same solvent? How do you know? No, because it depends on the temperature and the solubility of the solute.

2. Interpret for Table 2 the mass of sugar that would have to be dissolved in 100g of water to form a saturated solution at 20 degrees Celsius. 203.9

3. Determine which is more soluble in water: 17g of solute X dissolved in 100mL of water at 23 degrees Celsius or 26g of solute Z dissolved in 100mL of water at 23 degrees Celsius. Solute X would be more soluble because it has less mass.

4. Identify the type of solution you have if, at 35 degrees Celsius, solute continues to dissolve as you add more. An unsaturated solution.

5. Think critically. Explain how keeping a carbonated beverage capped helps keep it from going "flat." Pressure effects gases dissolving in liquids. You don't want to have a flat drink with no gas in it so the pressure must be kept on the gas to kept it in the bottle.

6. Applying math. Calculate cost. By volume, orange drink is ten percent each of orange juice and corn syrup. A 1.5-L can of the drink costs $0.95. A 1.5-L can of orange juice is $1.49, and 1.5 L of corn syrup is $1.69. Per serving, does it cost less to make your own orange drink or buy it? Buy it because the cost of it alone is 3.18 and separate is 1.90 ($).

Section Three: Particles in Solution

Vocabulary: ion: charged particles in the fluids that are in and around all the cells in your body electrolyte: compounds that produce solutions of ions that conduct electricity in water non-electrolyte: substances that form no ions in water and cannot conduct electricity ionization: process of forming ions dissociation: process in which an ionic solid, such as sodium chloride, separates into its positive and negative ions.

Picture Questions: 1. Probably yes because the ions move freely so they can produce electricity. 2. The antifreeze is evenly distributed and the solute particles block part of the surface, making it more difficult for the solvent to vaporize.

Reading Check: 1. Dissociation is separation into positive and negative ions and ionization is the forming of a new ion. A change is taking place in both.

Review Check:

Section Review:

1. Determine what has taken place, ionization or dissociation, if calcium phosphate (Ca3(PO4)2) breaks into Ca 2+ and PO4 3-. Dissociation because nothing new is being formed if is just broken down into positive and negative ions.

2. Identify what kinds of solute particles are present in water solutions of electrolytes and non-electrolytes. ?

3. Describe how an ionic substance dissociates in water. The water molecules surround the ions pulling them away from each other dissociating from each other. Now the ions are mixed with water.

4. Describe how the concentration of a solution influences its boiling point. If the solution is concentrated the particles are closer together so the boiling point would be higher because the particles would have a harder time evaporating.

5. Think critically. In cold weather, people often put salt on ice that forms on sidewalks and driveways. The salt helps melt the ice, forming a saltwater solution. Explain why this solution may not refreeze. Salt probably becomes a solute that rearranges the formation pattern making it harder for the saltwater to freeze again so then lowering its boiling point.

6. Applying math. Graph data. Use the following data points (0,12), (10,8), (20,4), and (30,0), to graph the effect of a solute on the freezing point of a solvent. Label the x-axis Grams solute and the y-axis Freezing point.

7. Calculate slope. Find the slope of the line you graphed in question 6. 2 1/2

Section Four: Dissolving Without Water

Vocabulary: nonpolar: materials that have no separated positive and negative areas

Picture Questions: 1. One must stir and mix the dressing to get both parts of this on their salad.

Reading Check: 1. Because it has a polar and nonpolar end in molecules. 2. The dirt is a nonpolar mixture so water won't get is out. 3. The vitamins may be absorbed by fat in your body.

Review Check:

Section Review:

1. Explain how a solute can dissolve in polar and nonpolar solvents. The solute must attract to the polar and nonpolar areas of the substance or element.

2. Explain the phrase "like dissolves like" and give an example of two polar "like" substances. When molecules of a nonpolar solvent can slip easily among the molecules of the nonpolar solvent.

3. Describe how soap cleans greasy dirt from your hands. Soap is nonpolar and polar so it attracts the nonpolar dirt on the hands.

4. Infer. Some small engines require a mixture of oil and gasoline. Gasoline evaporates easily. What conclusion can be drawn about the polarity of the engine oil? It is nonpolar because oil usually doesn't mix with polar objects so if both are nonpolar they should mix.

5. Think critically. What might happen to your skin if you washed with soap too often? If there is no dirt the hydrocarbon portion will be left on the skin instead of dissolving the dirt.

6. Applying math. Calculate mass. If 60mg of vitamin C in a multivitamin provides only 75 percent of he recommended daily dosage for children, how much is recommended? 80mg

7. Interpret data. To get the recommended 80mg of vitamin C, refer to Table 3 to determine approximately how much fresh orange juice you must drink. more than 2/3 a cup of fresh OJ

Science STATS:

1. 17 1/2 2. 17