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7. Solution Chemistry

7. Solution Chemistry. A solution is a mixture of two or more compounds in variable proportions. The compound in the higher amount is called the solvent. The other compound(s) are called solutes. Like dissolves Like. Outline 7.1 Solutions Are Mixtures 7.2 Formation of Solutions

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7. Solution Chemistry

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  1. 7. Solution Chemistry A solution is a mixture of two or more compounds in variable proportions. The compound in the higher amount is called the solvent. The other compound(s) are called solutes. Like dissolves Like Outline 7.1 Solutions Are Mixtures 7.2 Formation of Solutions 7.3 Chemical Equations for Solution Formation 7.4 Concentrations 7.5 Dilution 7.6 Osmosis and Diffusion 7.7 Transport across Cell Membranes

  2. Solutes are evenly distributed Solutes are not visible e.g. vinegar soda saline solution etc. Solution Colloidal Dispersion Colloidal particles are evenly distributed. Particle sizes range from 1 nm → 1 mm. Particles stay dispersed and don’t settle. Particles may settle in high speed centrifuge. Particles diffract light so solution may appear cloudy. e.g. milk soap solution protein solutions Suspension Particle sizes > 1 mm. Particles not evenly distributed. Settle with time. Particles settle rapidly in low speed centrifuge. “solution’ obviously heterogeneous e.g. Sand/silt in water red blood cells in saline

  3. Electrolytes A compound that produces ions when it dissolves in water is an electrolyte Solutions may be classified according to their ability to conduct electricity as …... Strong Electrolytes – fully dissociate in solution …… e.g. soluble ionic compounds MgCl2(s) (add water) → Mg2+(aq) + 2Cl-(aq). strong acids HCl (added to water) → H+(aq) + Cl-(aq). nonelectrolytes – may dissolve but do not “ionize” in aqueous solution. e.g. Glucose(s) (add water) ↔ Glucose(aq) Weak electrolytes – partially dissociate in solution …… e.g. weak acids CH3-COOH (added to water) ↔ H+(aq) + CH3-COO-(aq). acetic acid proton acetate ion. mostly some

  4. Concentration - A measure of how much solute is dissolved Units (general) - amount of solute amount of solution Molarity (M) - moles of solute or mol/L Liter of solution Milliequivalents per Liter (meq/L) - milliequivalents of solute Liter of solution this is the same as millimoles/L or mmol/L or mM for ±1 ions Parts per million ppm & Parts per billion ppb % (w/v) - ___g of solute___ 100 ml of solution (which is ~ 100 g for water)

  5. … or 138 mM or 0.138 M … or 5 mM or 0.005 M … or 4 meq/L • 1 mmol/2 meq = 2 mM or 0.002 M … or 110 mM or 0.110 M … or 30 mM or 0.030 M

  6. Practice Problems (page 267) Keep track of units! 7.24 What is the Molarity of 750 ml of solution containing 2.10 moles Na2SO4? 750 ml = 0.750 L 2.10 moles Na2SO4= 2.8 M 0.750 L 7.26 What is the Molarity of 500 ml of solution containing 45 g NaHCO3? 500 ml = 0.500 L 45 g NaCO3• 1 molNaCO3 = 1.07 M 0.500 L 84 g

  7. Practice Problems (page 267) 7.20 A .0 5% dextrose IV fluid contains 35meq/L of K+. A patient gets 235ml of this IV solution – How many moles of K+ did they receive? What is the MW of glucose (C6H12O6)? AW: C = 12.0, H = 1.0, O = 16.0 a) 29.0 b) 90.0 c) 180 d) 240 units are g/mol Dextrose is D-glucose How many grams of glucose did the patient in problem 7.20 receive? 5.0 g glucose • 235 ml = 11.75 g 100 ml What is the molarity of the solution in problem 7.20? 100 ml = 0.100 L 5.0 g glucose • 1 mol glucose = 0.28 M glucose 0.100 L 180 g

  8. Concentration - A measure of how much solute is dissolved Units (general) - amount of solute amount of solution Molarity (M) - moles of solute or mol/L Liter of solution 5.0 grams of glucose are dissolved in water to a final volume of 400 ml. How many moles of glucose were dissolved? a) 0.028 b) 0.035 c) 0.042 d) 1.0 What is the molarity of the glucose solution? a) 0.028 b) 0.035 c) 0.070 d) 1.0

  9. What is the w/v of NaCl that corresponds total electrolyte concentration of blood plasma? (= 154 mM or 0.154 M) 0.154 molNaCl• 58.5 g NaCl • 0.1 mol = 0.90 g NaCl= 0.90 % (m/v) 1 L 1 mol 100 ml 100 ml soln

  10. 8.5Dilution • One way to prepare solutions of lower concentration is to dilute a solution of higher concentration by adding more solvent.

  11. Dilution Calculations In a lab solutions are often prepared at a higher concentration than they are used. The higher concentration solution is often referred to as the stock solution. The solution required is prepared from the stock solution by dilution. Dilutions always use the following equation ….. C1V1 = C2V2 C = concentration (any units may be sued as long as they match on both side of the equation) V = Volume (any units may be sued as long as they match on both side of the equation) 1 = stock solution 2 = diluted solution

  12. Practice Problems (page 270) C1V1 = C2V2 7.38 How many ml of a 0.90% (m/v) NaCl solution can be prepared from 600 ml of a 9.0% (m/v) stock solution? 7.42 How would you prepare 2 L of 1 M MgCl2 from a 5M MgCl2 stock solution? 7.40 If 40 ml of a 6.0 M NaOH solution is diluted to a final volume of 200 ml, what is the resulting concentration of the solution? a) 30 M b) 1.0 M c) 0.8 M d) 1.2M

  13. Homework for Friday 7.58 7.66 7.68 7.70 7.74 7.84 7.86

  14. Osmosis and diffusion A solution is a homogeneous mixture. If you ‘tracked’ one solute molecule/ion in a solution over time, which of the following would you observe? a) the solute molecule would stay in the same place. b) the solute molecule would gradually move in a very random fashion. c) the solute molecule would slowly move but always in the same direction. d) the solute molecule would rapidly move through the solution in straight lines. The motion of a solute in a solution is called Brownian motion. Diffusion occurs when a fluid has and unequal distribution of a solute, and it moves to make the distribution uniform (or equal). Diffusionrequires a change in concentration over time and proceeds until the fluid becomes a homogeneous solution. (e.g. a drop of food coloring in a beaker diffuses until the beaker has a uniform distribution of color)

  15. Diffusion A solute is in a solution separated by a membrane. The pores in the membrane are larger than the solute. What will happen? Diffusion – particles will move from an area of high concentration to lower concentration.

  16. A solute is in a solution separated by a membrane. The solute particles are larger than the pores. What will happen to the solute molecules? What about the solvent molecules? (not pictured) Osmosis Solvent flow Osmosis – solvent particles will move from an area of high solvent concentration to lower solvent concentration. Or from an area of low [solute] to high [solute].

  17. Osmosis and Diffusion

  18. Colloidal Dispersion Blood Plasma contains large amounts of the protein Serum Albumin (and other proteins). The [protein] in blood is > [protein] in interstitial fluid (the fluid between cells). This creates COP (colloidal osmotic pressure). Colloidal particles are evenly distributed. Particle sizes range from 1 nm → 1 mm. Particles stay dispersed and don’t settle. e.g. protein solutions The pumping action of the heart also produces a hydrostatic pressure that opposes COP.

  19. HP < COP Fluid flows into veins carrying CO2 & waste HP > COP Fluid flows into cells carrying O2 & nutrients Venous capillary flow Cells of various tissues Arterial capillary flow

  20. Dialysis • The kidneys act to remove small waste molecules out of the blood through diffusion across membranes in the kidneys. • A person whose kidneys are failing can undergo artificial dialysis—called hemodialysis—to cleanse the blood. • In this process, blood is removed from the patientand passes through one side of a semipermeable membrane in contact on the opposite side with an isotonic dialyzing solution. • Urea and small waste molecules diffuse outof the passing blood and into the dialyzing solution, and the dialyzed blood returns to the patient.

  21. • How does • get into cell? Ions, nonpolar molecules, and polar molecules move across cell membranes using diffusion, facilitated transport, or active transport.

  22. Transport across CellMembranes • Small molecules like water and the nonpolar molecules O2, N2, and CO2 can diffuse directly through the cell membrane. • Diffusion moves solutes to equalize the concentrations on either side of a membrane. • This process does not require any additional energy so is also referred to as passive diffusion. • Other nonpolar molecules like steroids can also passively diffuse through cell membranes.

  23. Transport across CellMembranes • Molecules like ions and glucose molecules require the help of membrane proteins to cross the membrane (facilitated transport) • Such proteins are referred to as transporters or channels. • Active transport requires energy consumption (ATP).

  24. Chapter Seven Summary Solutions Are Mixtures Substances that release ions when they dissolve in waterare called electrolytes because the solution will conductan electrical current. (strong vs. weak) The concentration of a solution is the amount of solute dissolvedin a certain amount of solution. Fluid replacement solutions are often expressed in units of mEq/Lor in some cases mmol/L. Molarity is the moles of solute per liter of solution. Percent mass/volume {%(m/v)} expresses the ratio of the mass of solute (in g)to the volume of solution (in mL) multiplied by 100. %(m/v) is equivalent to the unit g/dL. (1 dL = 100 ml) Osmosis and Diffusion C1V1 = C2V2 Transport across Cell Membranes

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