Bio Sciences p H How to Make Buffer

Bio Sciences: p. H How to Make Buffer 1/30/2022

Bellwork What is Buffer Capacity? 1/30/2022

Objectives 1. State/ recall the components of Molarity, Molar Mass, and the conversion between m. L and L. 2. Write a generic protocol for preparing a buffer, given a buffer table 1/30/2022

Buffer Recall What is and buffer? “A solution that resists change in p. H when acid or base is added” 1/30/2022

Solution Measurement Recall Where is the easiest place to find the molar mass of a compound On the reagent container In order to make a solution you need to measure out specific masses or volumes of reagent (stock chemicals). To find grams or moles (a set number like a dozen) you will need the molar mass, M. M. or concentration of a reagent. 1/30/2022

Solution Measurement Finding Moles and Grams Recap M. M. = molar mass (g/mol) “x = what you have” Converting from moles to grams: 1/30/2022

Solution Measurement Finding Moles and Grams Recap Drill/ Quiz How many grams are there if you have 1. 0 mol and a molar mass of 44 g/mol? How many moles are there if you have 5. 0 grams and a molar mass of 121. 0 g/mol? 1/30/2022

Concentration, Molarity (M) is going to be the concentration unit we will be using, or pieces per volume. Molarity is moles, mol (a set number like Liter a dozen) per _____ of solution. 1/30/2022

Solution Measurement Finding Milliliters and Liters Volume units m. L = milliliters L = liters “x = what you have” Converting from m. L to L: Converting from L to m. L: 1/30/2022

Solution Measurement Finding Milliliters and Liters Drill/ Quiz How many m. L are there if you have 0. 5 L? How many L are there if you have 30 m. L? 1/30/2022

Components of a Buffer Which of the following can be components in a buffer? strong bases conjugate base* weak acids strong acids weak bases conjugate acid* salts indicators * Of weak A/B 1/30/2022

Ways to Prepare a Buffer 3 Common methods to make a Look up on a buffer Use p. Ka of weak acid/ Add Acid/ base and buffer table, base to determine adjust to desired p. H, trial and error our Preferred method Fast. Easy to prepare Easy to understand Additional p. H adj. is rare A lot of p. H adjusting Requires calc. and knowing buffer p. Ka Time consuming 1/30/2022 Easy to Understand Many choices Set recipes, that work most of time

Preparing a Buffer Protocol We will follow set steps to make buffer using a table. There will be times when you need to complete calculations and make adjustments; however, we will deal with that when the time comes. The handout “Buffer Preparation Protocol Using a Buffer Table” can be referred to any time you need to make a specified buffer. 1/30/2022

Compare Buffer Preparations With your partner Identify by highlighting key vocabulary/ concepts on “Buffer Preparation Protocol Using a Buffer Table” and “Standard Operating Procedure 1 x Tris TAE Buffer” by "skimming and scanning". Find at least three (3) similarities between the protocol and SOP and record in lab book. 1/30/2022

Closure Respond to ALL of the following prompts in regards to buffer preparation: ◦ I now understand. . . ◦ I would like to know more about. . ◦ I need more help with. . ◦ I could teach someone else to. . 1/30/2022