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Ch15.1 – Water and Aqueous Solutions Ex1) Draw H 2 O structure shape: bond angle: polar:

Ch15.1 – Water and Aqueous Solutions Ex1) Draw H 2 O structure shape: bond angle: polar:. Ch15.1 – Water and Aqueous Solutions O shape bent H H bond 105 ˚ O O polar yes H H H H Acts like a skin at surface (call this surface tension).

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Ch15.1 – Water and Aqueous Solutions Ex1) Draw H 2 O structure shape: bond angle: polar:

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  1. Ch15.1 – Water and Aqueous Solutions Ex1) Draw H2O structure shape: bond angle: polar:

  2. Ch15.1 – Water and Aqueous Solutions O shape bent H Hbond 105˚ O Opolar yes H HHHActs like a skin at surface (call this surface tension) H20 has high surface tension, low vapor pressure, high boiling point (compared to other covalent molecules) High surface ttension makes Add soap (surfactants-surface active agents) it stick to its self, defies gravity interfere with hydrogen bonding, bead spreads out. coin coin

  3. Ch15.1 – Water and Aqueous Solutions O shape bent H Hbond 105˚ O Opolar yes H HHHActs like a skin at surface (call this surface tension) H20 has high surface tension, low vapor pressure, high boiling point (compared to other covalent molecules) High s.t. makes it stick Add soap (surfactants-surface active agents) to its self, defies gravity interfere with hydrogen bonding, bead spreads out. All liquids have some amount of surface tension. coin coin

  4. Heat Capacity Water has a high specific heat capacity(ability to absorb energy without changing temp) - Instead of energy going in and increasing average K.E. (molecular motion), causes bonds to bend, twist, wiggle, stretch.

  5. Evaporation - water has a large heat of vaporization - 2260J/g Strong dipole forces, require lots of energy to break free. Ex2) How much heat energy is required to vaporize 2.0g of water?

  6. Evaporation - water has a large heat of vaporization - 2260J/g Strong dipole forces, require lots of energy to break free. Ex) How much heat energy is required to vaporize 2.0g of water? 2.0g 2260J = 4520J 1g Ammonia – HV = 1370 J/g Methane – HV = 500 J/g They vaporize much easier than water. - since N and C aren’t as electronegative, don’t have as strong hydrogen bonding. They have higher vapor pressure than water

  7. Evaporation - water has a large heat of vaporization - 2260J/g Strong dipole forces, require lots of energy to break free. Ex) How much heat energy is required to vaporize 2.0g of water? 2.0g 2260J = 4520J 1g Ammonia – HV = 1370 J/g Methane – HV = 500 J/g They vaporize much easier than water. - since N and C aren’t as electronegative, don’t have as strong hydrogen bonding. They have higher vapor pressure than water Water has low vapor pressure (only a little of it becomes a gas)

  8. Ice • Solid H20 is less dense than liquid (ice floats). • Ice Water • - water has its greatest density at 4˚C • (liquid, slow moving) • - important for life on earth. • - Most substances, solid is more dense than liquid • Exceptions besides H2O: • Bismuth, Antimony, some iron alloys • Ch15 HW#1 1-6

  9. Lab15.1 – Adhesion/Cohesion - due tomorrow - Ch15 HW#1 due at beginning of period

  10. Ch15 HW#1 1-6 1. What is surface tension? Why do particles at the surface of the liquid behave differently from those in the bulk of the liquid? 2. Describe the origin of the vapor pressure of water. 3. Why is it easier to wash a car with soapy water than just water alone? 4. Why does water have a relatively high boiling point?

  11. 5. How many kilojoules are required to vaporize 5.0g of water at its boiling point? 6. What unique characteristic of ice distinguishes it from other solids?

  12. 5. How many kilojoules are required to vaporize 5.0g of water at its boiling point? 6. What unique characteristic of ice distinguishes it from other solids?

  13. 5. How many kilojoules are required to vaporize 5.0g of water at its boiling point? 6. What unique characteristic of ice distinguishes it from other solids? Floats in its own liquid

  14. Ch15.2 – Aqueous Solutions - Pure water doesn’t exist in nature because water dissolves so many substances. When water dissolves a substance, the solution is called an aqueous solution. With any other solvent its is just called a solution. Solvent – dissolving medium (substance doing the dissolving) Solute – the dissolved particles in the solvent. - water will dissolve any ionic compound (to some degree) or any polar molecular compounds. - it wont dissolve oil because oil is nonpolar. “Like dissolves like”

  15. Ch15.2 – Aqueous Solutions - Pure water doesn’t exist in nature because water dissolves so many substances. When water dissolves a substance, the solution is called an aqueous solution. With any other solvent its is just called a solution. Solvent – dissolving medium (substance doing the dissolving) Solute – the dissolved particles in the solvent. - water will dissolve any ionic compound (to some degree) or any polar molecular compounds. - it wont dissolve oil because oil is nonpolar. “Like dissolves like” In polar solutions: ions or polar molecules are attracted to polarity of solvent. (some don’t dissolve if attractions between ions is stronger than attractions to solvent.) In nonpolar solutions: substance just mix If 2 solutions mix, the one in greater amount is the solvent.

  16. Electrolytes and Nonelectrolytes Electrolytes – ionic compounds conduct electricity when their ions are mobile. Conduct as a liquid (molten), or when aqueous (dissolved in solution) Do not conduct in the solid state - ions cant move around. Exs: NaCl conducts when dissolved in water, or when heated until it becomes molten. Doesn’t conduct as solid. (strong electrolyte) BaSO4 conducts when molten, poor conductor when dissolved in water because it is insoluble – doesn’t dissolve well. (weak electrolyte) Nonelectrolytes – covalent compounds. Never conduct electricity. Metals – conduct as solids or liquid Ch15 HW#2 + Density Rev

  17. Density Review 1) What is the density of a copper slug that a lab group masses at 180.01g and finds the volume to be 20.5cm3? 2) If the actual density is 8.96 g/cm3, what is the % error? 3) Glycerin: 1. Mass of dry grad. cylinder = 12.36g 2. Mass of glycerin & cylinder = 24.74g 3. Volume of glycerin = 9.8mL 4) Salt water solution has density 1.13g/cm3. Volume determined to be 8.0cm3. Find mass: 5) Mass a piece of aluminum at 90.20g. Its density is given as 2.80 g/cm3. Find the volume:

  18. Density Review 1) What is the density of a copper slug that a lab group masses at 180.01g and finds the volume to be 20.5cm3? D=m/v = 180.01g/20.5cm3 = 8.78g/cm3 2) If the actual density is 8.96 g/cm3, what is the % error? % error = l actual – exp l / actual x 100% = l 8.96 - 8.78 l / 8.96 x 100% = 2.0% 3) Glycerin: 1. Mass of dry grad. cylinder = 12.36g Mass of glycerin = 12.38g 2. Mass of glycerin & cylinder = 24.74g 3. Volume of glycerin = 9.8mL D = 12.38/9.8 = 1.26g/mL 4) Salt water solution has density 1.13g/cm3. Volume determined to be 8.0cm3. Find Mass: D = m/V  m = D.V = 1.13g 8.0 cm3 = 9.04g 1cm3

  19. 5) Mass a piece of aluminum at 90.20g. Its density is given as 2.80 g/cm3. Find the volume: D = m/V => 2.80 g/cm3 = 90.20g / V V = 90.20g / 2.80g/cm3 V= 90.20g 1 cm3= 32.3 cm3 2.80g

  20. Ch15 HW#2 7 – 12 7) Distinguish between a solution and an aqueous solution 8) Tablespoon of NaCl in water. ID solute & solvent. 9) Describe how an ionic compound dissolves in water. (picture from yesterday) 10) Which dissolves in water? a) HCl b) NaI c) NH3 d) MgSO4 e) CH4 f) CaCO3 g) Gasoline 11) Electrolyte and nonelectrolyte 12) Equation for how calcium chloride dissociates in water.

  21. Ch15 HW#2 7 – 12 7) Distinguish between a solution and an aqueous solution Solution – solute dissolved in a liquid (or gas) solvent Aqueous solution – solute dissolved in water 8) Tablespoon of NaCl in water. ID solute & solvent. 9) Describe how an ionic compound dissolves in water. (picture from yesterday) 10) Which dissolves in water? a) HCl b) NaI c) NH3 d) MgSO4 e) CH4 f) CaCO3 g) Gasoline 11) Electrolyte and nonelectrolyte 12) Equation for how calcium chloride dissociates in water.

  22. Ch15 HW#2 7 – 12 7) Distinguish between a solution and an aqueous solution Solution – solute dissolved in a liquid (or gas) solvent Aqueous solution – solute dissolved in water 8) Tablespoon of NaCl in water. ID solute & solvent. Solute – NaCl Solvent – water 9) Describe how an ionic compound dissolves in water. (picture from yesterday) 10) Which dissolves in water? a) HCl b) NaI c) NH3 d) MgSO4 e) CH4 f) CaCO3 g) Gasoline 11) Electrolyte and nonelectrolyte 12) Equation for how calcium chloride dissociates in water.

  23. Ch15 HW#2 7 – 12 7) Distinguish between a solution and an aqueous solution Solution – solute dissolved in a liquid (or gas) solvent Aqueous solution – solute dissolved in water 8) Tablespoon of NaCl in water. ID solute & solvent. Solute – NaCl Solvent – water 9) Describe how an ionic compound dissolves in water. (picture from yesterday) 10) Which dissolves in water? a) HCl b) NaI c) NH3 d) MgSO4 e) CH4 f) CaCO3 g) Gasoline 11) Electrolyte and nonelectrolyte 12) Equation for how calcium chloride dissociates in water.

  24. Ch15 HW#2 7 – 12 7) Distinguish between a solution and an aqueous solution Solution – solute dissolved in a liquid (or gas) solvent Aqueous solution – solute dissolved in water 8) Tablespoon of NaCl in water. ID solute & solvent. Solute – NaCl Solvent – water 9) Describe how an ionic compound dissolves in water. (picture from yesterday) 10) Which dissolves in water? a) HCl b) NaI c) NH3 d) MgSO4 e) CH4 polar cov ionic polar cov ionic nonpolar yes yesyesyes no f) CaCO3 g) Gasoline ionic nonpolar (not very soluble) no 11) Electrolyte and nonelectrolyte 12) Equation for how calcium chloride dissociates in water.

  25. Ch15 HW#2 7 – 12 7) Distinguish between a solution and an aqueous solution Solution – solute dissolved in a liquid (or gas) solvent Aqueous solution – solute dissolved in water 8) Tablespoon of NaCl in water. ID solute & solvent. Solute – NaCl Solvent – water 9) Describe how an ionic compound dissolves in water. (picture from yesterday) 10) Which dissolves in water? a) HCl b) NaI c) NH3 d) MgSO4 e) CH4 polar cov ionic polar cov ionic nonpolar yes yesyesyes no f) CaCO3 g) Gasoline ionic nonpolar (not very soluble) no 11) Electrolyte and nonelectrolyte ions in solution no ions in solution conducts electricity does not conduct electricity 12) Equation for how calcium chloride dissociates in water.

  26. Ch15 HW#2 7 – 12 7) Distinguish between a solution and an aqueous solution Solution – solute dissolved in a liquid (or gas) solvent Aqueous solution – solute dissolved in water 8) Tablespoon of NaCl in water. ID solute & solvent. Solute – NaCl Solvent – water 9) Describe how an ionic compound dissolves in water. (picture from yesterday) 10) Which dissolves in water? a) HCl b) NaI c) NH3 d) MgSO4 e) CH4 polar cov ionic polar cov ionic nonpolar yes yesyesyes no f) CaCO3 g) Gasoline ionic nonpolar (not very soluble) no 11) Electrolyte and nonelectrolyte ions in solution no ions in solution conducts electricity does not conduct electricity 12) Equation for how calcium chloride dissociates in water. CaCl2(s) Ca(aq)+2 + 2Cl(aq)–

  27. Ch15.3 – Suspensions, Colloids, Mixtures Solutions - Homogenous mixture Small particle size (0.1 – 1nm) Does not scatter light Particles don’t separate Exs: NaCl + water Particles cant be filtered KCl + water Suspensions - Heterogeneous mixture Large particle size (over 100nm) Scatters light (Tyndall effect) Particles separate (sediment forms) Particles can be filtered Ex: Muddy water Colloids - Mixture is in-between Medium particle size Scatters light Particles don’t separate from liquid Particles cant be filtered Exs: smoke, milk, marshmallows, gelatin, paint, aerosol sprays, whipped cream

  28. Emulsions - colloidal dispersions of liquid in liquids Ex: soapy water (one end of soap molecules is polar, attracts to H2O. Other end is nonpolar, will dissolve nonpolar oils.)

  29. Hydrated Crystals -water molecules attach to a salt crystal Ex1) Chemical name for Na2B4O7.10H2O HW#16a) Name Na2CO8.10H2O Ex 2) Formula for calcium chloride dihydrate HW#15a) Formula for sodium sulfate decahydrate Ex 3) Find the percent water by mass of CaCl2.2H2O

  30. Hydrated Crystals -water molecules attach to a salt crystal Ex1) Chemical name for Na2B4O7.10H2O sodium borate decahydrate HW#16a) Name Na2CO8.10H2O sodium carbonate decahydrate Ex 2) Formula for calcium chloride dihydrate Ca+2 Cl-1 2 H2O CaCl2.2H2O HW#15a) Formula for sodium sulfate decahydrate Ex 3) Find the percent water by mass of CaCl2.2H2O

  31. Hydrated Crystals -water molecules attach to a salt crystal Ex1) Chemical name for Na2B4O7.10H2O sodium borate decahydrate HW#16a) Name Na2CO8.10H2O sodium carbonate decahydrate Ex 2) Formula for calcium chloride dihydrate Ca+2 Cl-1 2 H2O CaCl2.2H2O HW#15a) Formula for sodium sulfate decahydrate Na+1 SO4-2 10 H2O Na2SO4.10 H2O Ex 3) Find the percent water by mass of CaCl2.2H2O

  32. Hydrated Crystals -water molecules attach to a salt crystal Ex1) Chemical name for Na2B4O7.10H2O sodium borate decahydrate HW#16a) Name Na2CO8.10H2O sodium carbonate decahydrate Ex 2) Formula for calcium chloride dihydrate Ca+2 Cl-1 2 H2O CaCl2.2H2O HW#15a) Formula for sodium sulfate decahydrate Na+1 SO4-2 10 H2O Na2SO4.10 H2O Ex 3) Find the percent water by mass of CaCl2.2H2O 1 Ca @ 40.1 = 40.1 2 Cl @ 35.5 = 71.0 % water: 36.0 x 100% = 2 H20 @ 18.0 = 36.0 147.1 147.1

  33. Hydroscopic – substance that pulls water out of the air (desiccant packs that come with your shoes and beef jerky) Ch15 HW#3 13 – 17

  34. Lab15.2 – Water of Hydration - due in 2 days - Ch15 HW#3 due at beginning of period

  35. Ch15 HW#3 13 – 17 13. 2 ways to distinguish a suspension from colloid. 14. Why don’t solutions exhibit Tyndall effect? 15b) Magnesium sulfate heptahydrate c) barium hydroxide octahydrate Mg+2 S04-2.7H20 Ba+2 OH-1. 8H20 16b) Magnesium carbonate trihydratec) Mg3(P04)2.4 H20 d) Calcium nitrate trihydrate e) CoCl2.2H2O

  36. Ch15 HW#3 13 – 17 13. 2 ways to distinguish a suspension from colloid. particle size, filtration, ability to stay suspended. 14. Why don’t solutions exhibit Tyndall effect? 15b) Magnesium sulfate heptahydrate c) barium hydroxide octahydrate Mg+2 S04-2.7H20 Ba+2 OH-1. 8H20 16b) Magnesium carbonate trihydratec) Mg3(P04)2.4 H20 d) Calcium nitrate trihydrate e) CoCl2.2H2O

  37. Ch15 HW#3 13 – 17 13. 2 ways to distinguish a suspension from colloid. particle size, filtration, ability to stay suspended. 14. Why don’t solutions exhibit Tyndall effect? Particles too small to scatter light. 15b) Magnesium sulfate heptahydrate c) barium hydroxide octahydrate Mg+2 S04-2.7H20 Ba+2 OH-1. 8H20 16b) Magnesium carbonate trihydratec) Mg3(P04)2.4 H20 d) Calcium nitrate trihydrate e) CoCl2.2H2O

  38. Ch15 HW#3 13 – 17 13. 2 ways to distinguish a suspension from colloid. particle size, filtration, ability to stay suspended. 14. Why don’t solutions exhibit Tyndall effect? Particles too small to scatter light. 15b) Magnesium sulfate heptahydrate c) barium hydroxide octahydrate Mg+2 S04-2.7H20 Ba+2 OH-1. 8H20 MgSO4.7H20Ba(OH)2.8H20 16b) Magnesium carbonate trihydratec) Mg3(P04)2.4 H20 d) Calcium nitrate trihydrate e) CoCl2.2H2O

  39. Ch15 HW#3 13 – 17 13. 2 ways to distinguish a suspension from colloid. particle size, filtration, ability to stay suspended. 14. Why don’t solutions exhibit Tyndall effect? Particles too small to scatter light. 15b) Magnesium sulfate heptahydrate c) barium hydroxide octahydrate Mg+2 S04-2.7H20 Ba+2 OH-1. 8H20 MgSO4.7H20Ba(OH)2.8H20 16b) Magnesium carbonate trihydrate c) Mg3(P04)2.4 H20 Mg+2 C03-2 3H20 magnesium phosphate MgCO3.3H20tetrahydrate d) Calcium nitrate trihydrate e) CoCl2.2H2O

  40. Ch15 HW#3 13 – 17 13. 2 ways to distinguish a suspension from colloid. particle size, filtration, ability to stay suspended. 14. Why don’t solutions exhibit Tyndall effect? Particles too small to scatter light. 15b) Magnesium sulfate heptahydrate c) barium hydroxide octahydrate Mg+2 S04-2.7H20 Ba+2 OH-1. 8H20 MgSO4.7H20Ba(OH)2.8H20 16b) Magnesium carbonate trihydrate c) Mg3(P04)2.4 H20 Mg+2 C03-2 3H20 magnesium phosphate MgCO3.3H20tetrahydrate d) Calcium nitrate trihydrate e) CoCl2.2H2O Ca+2NO3-13H2OCobalt Chloride dihydrate Ca(NO3)2.3H2O

  41. Ch16.1 – Properties of Solutions Solution Formation The nature of the solute and solvent determines if solute dissolves. These affect how fast: 1) Amount of surface are in contact. (only affects rate, not how much dissolves.) 2) Temperatures – faster when hotter. (increase freq of collisions) 3) Stir it – puts fresh solute in contact with fresh solvent. (agitation) Solubility - amount of a substance that will dissolve at a given temp. 36.2g of NaCl dissolve in 100g of H2O @ 25oC. NO MORE! - put more in, settles at bottom. Dynamic Equilibrium: NaCl Na+(aq) + Cl-(aq)

  42. Unsaturated solution – can dissolve more solute Saturated solution – contains the max amount of solute Supersaturated solution – “tricked” into dissolving more than max (pressure, temp) Mix 2 liquids: If they dissolve in each other  miscible If they are insoluble  immiscible Factors Affecting Solubility Solids and Liquids – solubility usually increases with temp (some exceptions) Gases dissolved in a liquid (like soda) – solubility decreases as temp increases – solubility increases as pressure above solution increases.

  43. Ex1) What is the solubility of: a) KBr @ 70˚C: _____g b) NaClO3 @ 100˚C: _____g c) NaCl @ 40˚C: _____g

  44. Henry’s Law: solubility pressure Ex2) If the solubility of a gas is 0.77 g/L at 350 kPa, what is its solubility at 100 kPa? (Temp held const) Ch16 HW#1 1 – 8

  45. Lab16.1 – Solubility - due in 3 days - Ch16 HW#1 due at beginning of period

  46. Ch16 HW#1 1. 2 components of solution: - gets dissolved (lesser amount) - does the dissolving (greater amount) 2. Name 3 factors that influence rate at which solute dissolve 3. What do to: a) make a saturated soln unsaturated Add more b) make an unsaturated soln saturated Add more 4. Explain miscible and immiscible

  47. Ch16 HW#1 1. 2 components of solution: Solute - gets dissolved (lesser amount) Solvent - does the dissolving (greater amount) 2. Name 3 factors that influence rate at which solute dissolve 3. What do to: a) make a saturated soln unsaturated Add more b) make an unsaturated soln saturated Add more 4. Explain miscible and immiscible

  48. Ch16 HW#1 1. 2 components of solution: Solute - gets dissolved (lesser amount) Solvent - does the dissolving (greater amount) 2. Name 3 factors that influence rate at which solute dissolve surface area heat it stir it 3. What do to: a) make a saturated soln unsaturated Add more b) make an unsaturated soln saturated Add more 4. Explain miscible and immiscible

  49. Ch16 HW#1 1. 2 components of solution: Solute - gets dissolved (lesser amount) Solvent - does the dissolving (greater amount) 2. Name 3 factors that influence rate at which solute dissolve surface area heat it stir it 3. What do to: a) make a saturated soln unsaturated Add more solvent b) make an unsaturated soln saturated Add more solute 4. Explain miscible and immiscible

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