Waterworks Operations II

1. Waterworks Operations II Lecture 2 Water Properties/Chemistry A Review http://www.mansfield.ohio-state.edu/~sabedon/biol1015.htm#hydrogen_bond

2. Key Words • Solute- The substance that dissolves to form a solution • Solvent- substance in which another substance is dissolved, forming a solution. • Solution- a medium consisting of solutes and solvents • Hydration- formation of water molecules around an ion. • Ions- electrically charged atoms • Cohesion- attraction of a water molecule to another water molecule via hydrogen bonding • Adhesion- attraction of a water molecule to a non water molecule

3. Substance in which another substance is dissolved, forming a solution. • Solute • Solvent • Solution

4. A medium consisting of solutes and solvents • Solute • Solvent • Solution

5. The substance that dissolves to form a solution • Solute • Solvent • Solution

6. Cohesion is _________. • The attraction of one water molecule to another resulting from hydrogen bonding • involves the attraction of a water molecule to a non-water molecule. • Influenced by water being a non polar molecule • All of the above

7. Key Words Sublimation is the phase change as a substance changes from a solid to a gas without passing through the intermediate state of a liquid. Triple POINT - The temperature and pressure at which the solid, liquid, and gas phases exist simultaneously. 273.16 K (0.01 oC) and a pressure of 611.73 pascals (ca. 6.1173 millibars, 0.0060373057 atm). Critical POINT - The temperature above which a substance will always be a gas regardless of the pressure. around 647 oK (374 oC or 705 oF) and 22.064 MPa (3200 PSIA or 218 atm). Freezing Point - The temperature at which the solid and liquid phases of a substance are in equilibrium at atmospheric pressure. Boiling Point - The temperature at which the vapor pressure of a liquid is equal to the pressure on the liquid. Normal (Standard) Boiling Point - The temperature at which the vapor pressure of a liquid is equal to standard pressure (1.00 atm = 760 mmHg = 760 torr = 101.325 kPa)

8. The phase change as a substance changes from a solid to a gas without passing through the intermediate state of a liquid. • Sublimation • Freezing point • Critical point • Boiling point

9. The temperature above which a substance will always be a gas regardless of the pressure. • Triple Point • Critical Point • Freezing point • Boiling point

10. Water • Water covers 70-80% of earths surface • 97% of earth’s water in the oceans! • 3% freshwater • 98% of the 3% of freshwater that is used as drinking water is groundwater!

11. What percentage of the water used in the United States comes from underground sources? • 45% • 30% • 60% • 90%

12. Nearly 95 percent of the rural population of the US relies on ground water. • True • False

13. Water • Life evolved in water, ~70% human body • Centigrade scale (0oC freeze) based on (100oC boil) water prop. • Most common molecule that exists as a liquid at ambient temperatures • Unique properties • high polarity, hydrogen bonding, cohesion, adhesion. high specific heat, high heat of vaporization, polar solvent

14. Which of the following is true about water? • Universal solvent • High heat capacity • High heat of vaporization • Liquid rather then a gas at room temperature • All of the above

15. + 104.5° + - Water • Structure • Tetrahedral (arrangement of electrons) • two hydrogen's (positive) • One oxygen (negative) • (O) two non-bonding electron pairs • Polar molecule • partial + (H) at one end, • partial – (O) at the other end • excellent solvent

16. Water is a polar molecule ? • True • False

17. Water (hydrogen bonding) hydrogen bond : bonding between oxygen and hydrogen (not strong) -Weak individually, stronger in larger quantities. Hydrogen bonding is responsible for: - liquid rather then gas at room temp - high specific heat, heat of vaporization - universal solvent - adhesion -cohesion- sticks together = liquid instead of changing to gas

18. Water (High Specific Heat) Specific Heat- The amount of heat needed to raise the temperature of one gram of a substance by 1°C. -a temperature increase is an increase in the motion of the molecules and atoms making up a substance. water molecules resist increasing their motion. (this is another way of saying that is water molecules resist the net breaking of hydrogen bonds) water resists heating; water has a very high specific heat.

19. Water High Heat Vaporizationboiling Heat of Vaporization- The amount of heat required to convert a unit mass of a liquid at its boiling point into vapor Vaporization is the breaking of hydrogen bonds (water has a lot of hydrogen bonding) water resists vaporizing (evaporating). Consequently, it takes a lot of heat to evaporate water. normal boiling point of 100 ºC, the latent specific latent heat of vaporization is 2260 kJ.kg-1.

20. Water High Latent Heat of Fusion melting Latent Heat of Fusion- the amount of heat required to convert a unit mass of the solid into the liquid without a change in temperature Need to add a lot of energy to break apart hydrogen bonds. Water has a heat of fusion of 143 Btu/lb.

21. Which of the is responsible for water being a liquid rather then gas at room temp? • Hydrogen bonding • High heat capacity • High heat of vaporization

22. The amount of heat required to convert a unit mass of the solid into the liquid without a change in temperature? • Hydrogen bonding • Specific Heat • Heat of vaporization • Latent Heat of Fusion

23. The amount of heat required to convert a unit mass of a liquid at its boiling point into vapor ? • Hydrogen bonding • Specific Heat • Heat of vaporization • Latent Heat of Fusion

24. The amount of heat needed to raise the temperature of one gram of a substance by 1°C? • Hydrogen bonding • Specific Heat • Heat of vaporization • Latent Heat of Fusion

25. Hydrochloric acid is a better solvent then water ? • True • False

26. Heating/Cooling Curve 100oC 0oC Freezing is the phase change as a substance changes from a liquid to a solid. Melting is the phase change as a substance changes from a solid to a liquid. Condensation is the phase change as a substance changes from a gas to a liquid. Vaporization is the phase change as a substance changes from a liquid to a gas.

27. Gas Liquid Uptake of heat by 1 kg of water, as it passes from ice at -50 ºC to steam at temperatures above 100 ºC Solid A: Rise in temperature as ice absorbs heat.B: Absorption of latent heat of fusion.C: Rise in temperature as liquid water absorbs heat.D: Water boils and absorbs latent heat of vaporization.E: Steam absorbs heat and thus increases its temperature.

30. Water (Universal Solvent) Water tends to very effectively dissolve hydrophilic (water loving) substances Phil Lesh

31. Water • Solvent • high polarity • good solvent for polar (salt) compounds

32. Hydrophilic compounds have an affinity to water and are usually charged or have polar side groups to their structure that will attract water. Hydrophobic are water hating compounds that are repelled by water and are usually neutral (no charge.)? • True • False

33. Water Why does ice float? Ice is less dense than water, therefore it floats. Solid water molecules form a ordered crystal through hydrogen bonding that spaces the molecules farther apart than when they were in a liquid (less dense).

34. Water liquid • Density ice The density of solid water is actually less than it could otherwise be because hydrogen bonded water is packed slightly less favorably than could be achieved without hydrogen bonding

35. ammonia vinegar 0 7 14 Great Salt Lake pure water acid rain acid mine drainage sea water

36. Activity

37. Iron Mountain, California -sulfide minerals oxidized • produces sulfate, metals, acidity (H+) • pH decreases • reduced metals released, then oxidized • mainly Fe(II) to Fe(III) • metals precipitate as hydroxides (Fe(OH)3) • hydroxide (OH-) consumed by metals • pH decreases • pH as low and lower than –3 recorded • {H+} = 103 • [H+] = 103 M???

38. vinegar Iron Mountain, California 7 -4 0 pure water acid rain acid mine drainage sea water -3.6

39. Concentration • Mass per volume • milligram per liter (mg L-1) • microgram per liter (g L-1) • nanogram per liter (ng L-1) • Moles per volume • moles per liter (M) • logarithmic scale pH = -log {H+} Molarity: M =  moles of solute  or  M = mol                1 Liter if solution       L

40. Concentration • Mass per mass • parts per thousand (per mil or %O) • parts per million (ppm) • parts per billion (ppb) • parts per trillion (ppt) • 1000 milliliters (ml) in a liter (L), • 1000 millimoles (mM) in a mole • 1,000,000 micrograms (µg) in a gram.

41. % to Mg/L You can memorize or set up a ratio. Its your choice Rule 1. to convert mg/L (ppm) to % multiply by 0.0001 Rule 2. to convert % to mg/L (ppm) multiply by 10,000 Rule 3. Ratio for percent to mg/L: Molarity:    M =  moles of solute      or    M = mol                   1 Liter if solution                  L

42. % Solutions/Solids A 1% NaCl solution is made by adding 1 g NaCl (a solid) to enough water to equal a final volume of 100 ml. A 1 % ethanol solution is made by adding 1 ml ethanol (a liquid) to enough water to equal a final volume of 100 ml To figure out how much of a solid you need to make up a percent solution (mass/volume) * (volume). EX: How do you make up 1 L of a 15% glucose solution? (15g glucose/100 ml) * 1000 ml = 150 g glucose. You would measure out 150 g glucose and then add enough water to have a final volume of 1000 ml.

43. % Solutions/Liquid To figure out how much of a liquid you need to make up a percent solution (volume material/volume solution) * (total final volume). For example: How do you make up 0.3 L of a 15% ethanol solution? (15ml ethanol/100 ml) * 300 ml = 45 ml ethanol. You would measure out 45 ml of ethanol and then add water to a final volume of 300 ml.

44. Molar Solutions When making up molar solutions from pure starting materials, you need to know the weight of a mole of the material, and the desired final volume. For example, the following are some molar weights: Material Weight of 1 mole NaCl 58.5 g glucose 180 g CaCl2 111 g NaOH 40 g To figure out what mass of material you need to make up a solution: (g/mole) * (mole/L) * L

45. Molar Solutions (g/mole) * (mole/L) * L Examples: To make 1 L of 1 M NaCl, you need: (58.5 g NaCl/mole) * (1 M / L) * 1 L = 58.5 g NaCl. To prepare the solution, measure 58.5 g of NaCl and add enough water so the final volume is equal to 1 L. To make 300 ml of 10 mM CaCl2, you need (111 g CaCl2/mole) * (0.01 mole/L) * 0.3 L = .333 g CaCl2. To prepare the solution, measure out 0.333 g CaCl2, and enough water so that the final volume is 300 ml.

46. Dilutions The relationship between starting concentration, final concentration, and dilution is: Ci * D = Cf where Ci = initial concentration, Cf = final concentration, and D = dilution. For example: How do you dilute a 1000 mM stock of glucose to give you a final concentration of 10 mM? D = Cf/Ci = 10 mM / 1000 mM = 1/100. You need to dilute the concentrated stock 1/100, so you could mix 1 ml of your stock with 99 ml of water. Another example: How do you dilute 70% ethanol to obtain 15% ethanol? D = Cf/Ci = 15%/70% = 15/70 You could take 15 ml of your stock and add 55 ml of water.

47. M1V1=M2V2 M1V1 = M2V2 and solve for any quantity we wish to. 1 is starting (concentrated) and 2 is ending (dilute) For example suppose we want to make 100 ml of a .10 M solution from a stock solution of 6M strength Using the M1V1 = M2V2equation M1V1 = M2V2 (100)(.10)  =   (x) (6) or 6x = 10, x = 1.67ml This means if we place 1.67 ml of the concentrated solution into a graduated cylinder and add enough water to form 100 ml we have the correct strength solution.

48. Nightly Competition

49. The objectives for this week to become familiar with the fundamentals of water and its unique chemical properties have been met. • Strongly Agree • Agree • Disagree • Strongly Disagree