Unit 10 Review 2011

1. Describe the following terms Solution Solvent Solute Soluble Insoluble Miscible Immiscible Homogeneous mixtures of 2 or more substances Dissolving medium Substance that dissolves Will dissolve Won’t dissolve Liquids are soluble in one another Liquids aren’t soluble in one another

2. Examples of the solutions Solid in a liquid Gas in a liquid Solid in a solid Gas in a gas Salt water Carbonated beverage Steel/braces Air

3 Describe what happens as a crystal of salt (NaCl) dissolves in water. Charged ends of water are attracted to the ions in salt This attraction is strong enough to pull the ions away

4 How is the dissolving process different in sugar (compared with salt)? OH bonds attract H of H 2 O molecules until sucrose molecule is surrounded by many H 2 O molecules, which then pull entire sucrose molecule away

5 Why doesn’t oil dissolve in water? Would oil dissolve in anything? Oil is nonpolar and water is polar. Oil would dissolve in a nonpolar solvent.

6 What is solubility? Maximum amount of solute that will dissolve in a given amount of solvent at a specific temperature and pressure.

7. How does temp affect solubility? For solids? For gases? –What else changes gas solubility? As temp increases, solubility increases As temp increases, solubility decreases pressure

8 What three things can be done to increase the rate at which a solid dissolves? a.Agitate the mixture b.Increase surface area of solute c.Increase temperature of solvent

9 Dissolving is a Physical or Chemical change. PHYSICAL

10 How would you prepare a supersaturated sugar solution? Include the term “seed crystal”. Make a saturated solution at a high temperature. Then cool slowly so excess solute remains dissolved at a lower temp. when a seed crystal is added, the entire solution will crystalize.

11 What is one test you could do to determine if a solution was saturated, unsaturated, or supersaturated? Describe how the results would be different for unsaturated, saturated, supersaturated solutions. Add more solute: unsaturated solution, it will dissolve saturated solution, it won’t dissolve supersaturated solution, a seed crystal will cause the solution to crystallize

12 Water is known as the: Universal solvent

13 What does solution concentration describe? Molarity: amount of solute dissolved in a given amount of solvent

14 What do we use to describe solution concentration in chemistry? Molarity

15 If a solution is “strong” it is If a solution is “weak” it is concentrated dilute

16 What does it mean to dilute a solution? What equation do we use for dilutions? To lower its concentration “water it down” M 1 V 1 = M 2 V 2

17 What is the molarity of a sodium chloride solution that contains 1.73 moles in 3.94 L of solution?

18 What is the molarity of sodium hydroxide solution that contains 23.5 g NaOH in mL of solution?

19 How many grams of potassium nitrate are in 275 mL of 1.25 M solution?

20 How many mL of 3.25 M hydrochloric acid would contain 16.0 grams of solute?

21 You have 12.0 M HCl in your stock room, how would you prepare mL of 2.50 M HCl solution? (12.0 M)(x) = (2.50 M)(600.0 mL) X=125 mL Measure out 125 mL of stock solution. Add 475 mL of distilled water.

22 How would you correctly prepare mL of a 3.0 M solution of NaOH from solid solute? NaOH Measure out 60 g of NaOH (s) Add water to the mL line

23 How would you prepare 500 mL of 3.0 M NaOH from 12.0 M concentrated stock solution? (12.0 M)(X) = (3.0 M)(500 mL) X=125 mL Measure out 125 mL of stock solution. Add it to 375 mL of distilled water

26 An excess of zinc is added to 125 mL of M HCl solution. What mass of zinc chloride is formed? Zn + 2HCl  ZnCl 2 + H 2

27 When determining solubility remember: “like dissolves like”

28 Polar/Nonpolar molecules will dissolve in water Polar

29 Polar molecules: one of these shapes: Must have ______ bonds (electronegativity difference between ) Dumbbell, bent, trigonal pyramidal Polar covalent

30 Molecules that won’t dissolve in water include anything with ____ bonds (electronegativity differences less than 0.4) Symmetrical shapes such as: These substances might dissolve in: nonpolar Linear, trigonal planar, tetrahedral Oil

31 Determine whether or not the following chemicals will dissolve in water. Circle the ones that will MgCl 2 SeO 2 SiO 2 PCl 3 Ionic