Chemical Solution Preparation Biotechnology I Chemical Solution Preparation Property of CTE Joint Venture

Essential Questions What are the components of a solution How is a solution’s density defined? How is solution concentration defined? What are common concentration units used for making chemical solutions? How is concentration calculated? Property of CTE Joint Venture

Solution: What is a Solution A solution is a homogeneous mixture of two or more substances (solvent and solute). A solution may exist in any phase (solid, liquid, or gas). Property of CTE Joint Venture

Solution Composition Solutions are composed of at least two components. Solute-The substance dissolved in the solution (usually what is measured out). Example – glucose, NaCl Solvent: The substance that does the dissolving. Example: water – universal solvent Property of CTE Joint Venture

Types of Solutions Cont. Homogeneous solution: Solution composed of only one phase Heterogeneous solution: Solution composed of more than one phase Which of these is a homogeneous solution? 1 or 2 1 Property of CTE Joint Venture

Units Important in Solution Preparation Common units Volume –L, mL, mL Mass – kg, g, mg, mg Property of CTE Joint Venture

Definition of Mole A unit of measurement or 6.023x1023 somethings used in chemical quantity expressions Property of CTE Joint Venture

Why a Mole? Because molecules that make up biological and chemical solutions are so small, we have to work with an extremely large amount of them. Rather than use really big numbers, the value of the mole was created. 1 mole = 6.023 x 1023 molecules Property of CTE Joint Venture

Molar Mass When using chemicals, molar mass is used. Molar Mass (MM): The number of grams in 1 mole Ex. NaCl = 58.44 g/mole Property of CTE Joint Venture

Molar Mass Determination Obtained from chemical label on stock bottle Property of CTE Joint Venture

Molar Mass determination Looking at chemical formula and a periodic table Ex. NaCL (chemical formula for sodium chloride) Na has a atomic mass of 22.99 g/mole Cl has a atomic mass of 35.45 g/ mole Molar Mass determined by adding the atomic masses 22.99 + 35.45 = 58.44 g/mole Property of CTE Joint Venture

  In order to convert between mass and volume the density of a substance needs to be known. Many times found on a stock chemical label. Property of CTE Joint Venture

Density Calculation Triangle Trick Density = Mass / volume Mass = Density X Volume Volume = Mass / Density To use the triangle trick, cover up the unit you want to calculate and then perform the mathematical operation either multiplication or division Property of CTE Joint Venture

Solution Concentration- Units of Measurement Biotechnology I

Concentration Concentration: The amount of substance in a defined space or volume Defined space or volume Amount of substance

Common Concentration Units: Percent (%) Two types commonly used in Biotechnology:    

SOP for Making w/v % Solution Convert (w/v) % to a decimal Convert volume to mL Multiple the decimal x the total volume to determine how much solute to weigh out Dissolve solute in small amount of water Bring to final total volume with water in graduated cylinder Property of CTE Joint Venture

Common Concentration Units- Molarity SOP for Making a Molar solution Determine final volume needed and convert unit to L Determine final concentration and convert to Molarity Determine the molar mass of the solute either determined from periodic table or taken from chemical stock bottle To determine mass use the following calculation g of powder = Molar Mass X Concentration ( in M) X Volume (in L)

Solution Preparation Equipment Here are some of the more common pieces of equipment you will use to make solutions Graduated cylinder Balance Magnetic stir plate and bar Pipets Beakers Property of CTE Joint Venture

Making Solutions: Cautions Mixing order: Always add Acids or Bases to water. Never add water to Acids or Bases Property of CTE Joint Venture