Water

What does one molecule of water contain?

What kind of bond holds water together?

Is the bond that holds water together strong or weak?

Water has several important functions:

a.

b.

c.

Water is polar. What does polar mean?

How does water interact with other water molecules?

How does hydrogen bonding occur?

Draw a picture depicting the difference between covalent bonds and hydrogen bonding related to water.

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Adhesion:

Example-

Cohesion:

Example-

In what three states of matter does water exist?

1.

2.

3.

Solid Liquid =

Gas Liquid =

Liquid Solid =

Liquid Gas =

Water has a high specific heat. What is specific heat?

2

Water demonstrates surface tension. What is surface tension?

Example-

What is capillary action? How does capillary action benefit plants?

Water is a solvent. What is a solvent?

Can water dissolve anything? Why?

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Water Homework

1) Fish survive through severe winters because of the property of water that allows water to —a. form chemical bonds as it freezes, raising the water temperature below the iceb. increase in density while it freezes, dissolving more oxygen from the airc. expand when it freezes, creating a floating and insulating layer of iced. precipitate vital nutrients when it freezes, increasing the food supply

2) What characteristic of water remains the same no matter what is dissolved in it?a. The ratio of hydrogen to oxygenb. The ability to refract lightc. The hydroxide ion concentrationd. The freezing temperature

3) If the properties of water were to change so that the solid form was denser than the liquid form, organisms living in a cold pond environment would be less likely to survive because water would no longer —

a. dissolve enough oxygen from the airb. produce solutions containing vital nutrientsc. remain neutral, instead becoming highly acidicd. produce a floating insulating layer of ice 

4) When water and oil are shaken together, they might appear mixed for a time, but soon separate into layers. Oil and water are not soluble in each other, so they are said to be immiscible. Which of the following factors is the reason oil and water are immiscible.?

a. The temperature it too lowb. They were shaken but not consistently stirredc. No catalyst was addedd. Oil is nonpolar and water is polar. 

5) Table salt, the ionic compound sodium chloride, dissolved in water. Water’s ability to dissolve sodium chloride is related to the

a. Number of protons present in each atom’s nucleus.b. Number of electrons present in a water molecule.c. Polarity and structure of water.d. Amount of solution you are trying to make.

6) Water will not dissolve nonpolar substances , such as grease on clothing. However, adding soap to the water helps remove the grease from the fabric. The best explanation as to why this process occurs is that…

a. Soap is an ionic substance and ionic substances dissolve in both water and greaseb. Soap molecules contain sodium or potassium ions, which dissolve greasec. Soap molecules have a polar end that dissolves in water and a nonpolar end that

dissolves in greased. Water does not dissolve the grease; water just washes the grease away

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7) What type of bond holds the hydrogens and oxygen in water together?______________________

Is this type of bond considered a strong or a weak bond?________________________________

8) Why is water considered a polar molecule?

9) _____________________ bonding makes water molecules ‘stick’ together. When water

sticks to other water molecules it is called, ______________________. When water

molecules stick to other molecules it is called ____________________.

10) How does the structure of water cause it to form hydrogen bonds?

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Solutions

What does soluble mean?

What is a solution?

What is a saturated solution?

What is an unsaturated solution?

What is a supersaturated solution?

There are 2 part to a solution- what are they? Draw a picture to help remind you.

Example:

When 4 g of Kool-Aid is mixed with 100 g of water, what is the solute?

What is the solvent?

Factors affecting solubility

1. Types of solvents and solutes- what does “like dissolves like” mean?

2. Pressure

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How does pressure affect the solubility of liquids and solids?

How does pressure affect the solubility of gases?

What does Henry’s law say?

3. Temperature

How does temperature affect the solubility of liquids and solids?

How does temperature affect the solubility of gases?

Factors affecting rates of dissolving

1. Surface area

How can one change the surface area of a substance?

How does changing the surface area affect the rate of dissolving?

2. Agitation

What are examples of agitation?

How does agitating a substance affect the rate of dissolving?

3. Heat

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How does heat affect the rate of dissolving for liquids and solids?

How does heat affect the rate of dissolving for gases?

4. Pressure

How does pressure affect the rate of dissolving for liquids and solids?

How does pressure affect the rate of dissolving for gases?

Electrolytes

What is an electrolyte?

What does on electrolyte solution contain?

Types of Electrolytes

1.

2.

3.

Examples:

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Solubility Homework

1. Identify the solute and solvent in the following solutions:

a) 10.0 g of sugar & 40.0 g of water solute: ____________solvent: ___________

b) 18.0 L of nitrogen & 12.0 L of oxygen solute: ____________solvent: ___________

2. Will sugar dissolve faster in hot tea or cold tea? Why?

3. Would higher pressure make sugar dissolve faster in tea?

4. What type of electrolyte are ionic compounds? _____________

What type of electrolyte are covalent compounds? ___________

What type of electrolyte are organic compounds? ____________

5. Circle the correct type for the following solutions:

a) NaCl (aq): electrolyte or nonelectrolyte

b) CCl4 (l): electrolyte or nonelectrolyte

c) O2 (g): electrolyte or nonelectrolyte

6. A 0.2 g crystal of gypsum dissolves very slowly in 100 mL of water while the water is stirred. Which of these would cause the gypsum to dissolve faster?

  a) Decreasing the water temperature c) Stopping the stirring b) Lowering the air pressure d) Crushing the crystal

7. Which of the following salts has the greatest solubility in water?

a) CaCO3 b) FeS c) HgCl2 d) KClO4

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Solubility Rules

a-c: Determine if the product will be a precipitate (solid in solution) or aqueous (dissolve in water).

Steps:1. Predict the compound.

2. Use the solubility chart.3. Conclude whether solid or aqueous.

a. Nitrate reacts with sodium.

b. Chlorine reacts with silver (I).

c. Carbonate reacts with sodium.

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Net Ionic Equations

What is a net ionic equation?

Steps:1. Balance the equation and label compounds (solid, liquid, gas, aqueous).2. Break the aqueous compounds apart.3. Cancel any elements that are identical on both sides.4. Write the remaining elements = net ionic equation.

a. A solution of NaI is combined with a solution of Pb(NO3)2 to produce PbI2 and NaNO3.

b. Sodium chloride + lead (II) sulfate produces sodium sulfate + lead (II) chloride.

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Net Ionic Equations Homework

1. potassium chloride + lead (II) nitrate potassium nitrate + lead (II) chloride

a.

b.

2. calcium chloride + sodium carbonate calcium carbonate + sodium chloride

a.

b.

3. iron (III) sulfate + lithium carbonate iron (III) carbonate + lithium sulfate

a.

b.

4. iron (III) chloride + sodium sulfide iron (III) sulfide + sodium chloride

a.

b.

5. ammonium phosphate + magnesium nitrate ammonium nitrate + magnesium phosphate

a.

b.

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Solubility Table

Based on the solubility table above, decide whether each of the following is a saturate, unsaturated or supersaturated solution.

a. 50 g of KCl in 100 g of water at 90 °C.

b. 50 g of KCl in 100 g of water at 60 °C.

c. 70 g of KNO3 in 100 g of water at 70 °C.

d. 50 g of KNO3 IN 50 g of water at 60 °C.

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Solubility Curve Homework

1. How many grams of potassium nitrate can be dissolved in 100 mL of water at 60 degrees Celsius?

2. How many grams of potassium nitrate will saturate 100 mL of water at 10 degrees Celsius?

3. How many grams of potassium nitrate will precipitate (fall out of solution) if 100 mL of a saturated solution of potassium nitrate at 60 degrees Celsius is cooled to 10 degrees Celsius?

4. 100 mL of water at 50 degrees Celsius can hold _____ grams of ammonium chloride.

5. 100 mL of water at 80 degrees Celsius can hold _____ grams of potassium chlorate.

6. How many grams of sodium nitrate will precipitate out of a 100-mL solution of sodium nitrate if the solution is cooled from 80 degrees Celsius to 50 degrees Celsius?

7. If 50 grams of potassium chloride are dissolved in 100 mL of water a 55 degrees Celsius, will the solution be saturated, supersaturated, or unsaturated?

Solubility (grams / 100-mL water) Temperature (degrees Celsius)65503525

20 6010 808 100

The following data describes the solubility of the gas, ammonia. Graph the data on the graph given and connect the points. Answer the questions that follow the graph.

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Graph:

8. What phase is ammonia in? How do you know?

9. Will 40 grams of ammonia dissolve in 100 mL of water at 30 degrees Celsius?

10. Is this solution saturated, unsaturated, or supersaturated?

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Molarity

Which solution is more concentrated?

What is molarity?

What is the formula for molarity?

Reminders-1. If you are given grams of the solute, you MUST convert into moles (divide by molar

mass). If given moles, go to step two.2. If you are given milliliters of the solute, you MUST convert into liters (divide by 1000).

If given liters, go to step three.3. Use the formula to solve.

a. Calculate the molarity of a solution prepared by mixing 1.25 moles of potassium permanganate (KMnO4), in enough water to make a 0.750 L solution.

b. Calculate the molarity of a solution made with 23.8 grams of iron chloride (FeCl3) dissolved in 5000.0 mL of water.

c. What is the volume, in mL, of a 2.5 M solution containing 45.5 grams of solute (KCl) in water?

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Molarity Homework

1. Calculate the molarity, M, of a solution prepared by dissolving 20.0 g of NaCl in 1.0 L of water.

2. Calculate the molarity, M, of a solution prepared by dissolving 3.5 g of Ca(OH)2 in enough water to make 100.0 mL of solution.

3. Determine the molarity if 0.25 g of Pb(NO3)2 is dissolved in enough water to make 500.0 mL of solution.

4. What would be the volume, in liters, of a 2.00 M solution made with 6.00 moles of LiF?

5. How many moles of CaCl2 would be used in the making 300.0 mL of a 5.0M solution?

6. How many moles of Sr(NO3)2 would be used in the preparation of 2.50 L of a 3.5 M solution?

7. Calculate the liters needed to prepare a 12.5 M solution containing 31.52 grams of CuOH. (Remember to convert to moles first)

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Dilution

What could you do if you have one concentration (M) of a solution and you need a less concentrated solution?

What are dilutions used for?

What does it mean to dilute a solution?

Equation for dilution:

a. You have 53 mL of a 1.5 M solution of NaCl, but 0.8 M solution is needed. How many mL should you add?

b. 50 mL of a solution are diluted to a volume of 100 mL. The concentration of the diluted solution is 2 M. What was the concentration of the original solution?

c. What is the molarity of the solution that results from diluting 20.0 mL of a 4.00 M solution to a new volume of 68.3 mL?

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Dilution Homework

Directions: Acids and bases are usually purchased in concentrated form. Rarely, however, do we want to use the acid or base in its concentrated form – we must dilute it to the exact concentration we want. Use the table below to help you answer the following questions. As always, show your work to earn full credit.

Concentrated Solution Molarity of Concentrate (M)Ammonium Hydroxide (NH4OH) 14.5

Formic Acid (HCOOH) 23.6Hydrochloric Acid (HCl) 12.1Hydrofluoric Acid (HF) 28.9

Nitric Acid (HNO3) 15.9Perchloric Acid, 60% (HClO4) 9.1

Phosphoric Acid (H3PO4) 14.8Potassium Hydroxide (KOH) 11.7Sodium Hydroxide (NaOH) 19.4

Sulfuric Acid (H2SO4) 18.0

1. What volume of concentrated hydrochloric acid is needed to make 3.0 L of 1.0 M HCl?

2. What volume of concentrated ammonium hydroxide is needed to make 250 mL of 0.5 M NH4OH?

3. To perform an experiment, you need 0.300 L of 6.0 M nitric acid. You go to the acid cabinet and discover that you have 100 mL of concentrate. Will you have enough acid to complete the experiment? Show your calculation and explain your answer. (Hint: Calculate volume needed, then compare to the 100 mL that you have)

4. You mix 30 L of an unknown, concentrated acid with water and get 222 L of a 2.0 M acid solution. What type of acid is it?

5. You mix 128 mL of an unknown, concentrated acid with water and get 1.54 L of a 1.5 M acid solution. What type of acid is it?

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Solutions Review

1) Sodium chloride exists mainly as ions and will conduct electricity. This substance is an _____________ (electrolyte or nonelectrolyte)

2) Why is soap effective in dissolving substances?

3) Will these reactions produce a precipitate (solid)?

a) 3 KBr + AlPO4 K3PO4 + AlBr3 b) Na2CO3 + CaCl2 CaCO3 + 2 NaCl

4) Which of the examples in the table below illustrates a nonpolar solute in a polar solvent?

Solute WaterCalcium Carbonate InsolubleNaphthalene InsolubleEthanol SolubleUrea Soluble

5) What factors increase the rate of solubility of a solid substance in water?

Why does grinding the solute increase the rate of solubility of a solid substance in water?

What effect does stirring have? How about temperature?

6) The molarity of a diluted solution will be ______________ (higher, lower) than the molarity of a concentrated solution.

7) Which term refers to water’s attraction to other substances that have full or partial electrical charges?

8) Ice floats when placed in liquid water because:

9) List the definitions for cohesion and adhesion:

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10) Which part(s) of a water molecule has/have a partial negative charge?

11) How many grams of KCl can be dissolved in 100g of water at 10°C? ______________________

12) How many grams of NaCl can be dissolved in 50g of water at 90°C? ______________________

13) At 30°C, 30g of NaNO3 is dissolved in 100g of water. Is this solution supersaturated, saturated or unsaturated?

____________________

14) At 80°C, 80 g of KCl is dissolved in 100 g of water. Is this solution supersaturated, saturated or unsaturated?

15) A saturated solution of NH3 is formed from one hundred grams of water. If the saturated solution is cooled from 31°C to 10°C, how many grams of precipitate are formed?_______________

14) Calculate the molarity, M, of a solution prepared by dissolving 56.0 grams of AlCl3 in 250.0 mL of water.

15) Determine the volume in Liters of the solution if the molarity is 2.96 M and contains 6.8 moles of sodium sulfate, Na2SO4.

16) 100 ml of a 1.5 M solution are diluted to make a 0.6M solution. What is the volume of the resulting solution?

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17) 200 ml of a 6 M solution are diluted to 440 ml. What is the concentration of the resulting solution?

18) A solution of NaI is combined with a solution of Pb(NO3)2 to produce PbI2 and NaNO3.

a. Balanced chemical equation including proper states for this reaction:

b. Net ionic equation:

19) sodium chloride + lead (II) sulfate produces sodium sulfate + lead (II) chloride .

a. Balanced chemical equation including proper states for this reaction:

b. Net ionic equation:

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For each reaction:a) Write the balanced chemical equation including proper states ( ) for the following

reaction.b) Find the net ionic equation for the reaction.