Percent Alcohol in Wine Week 1 Lab S117 Fall 2011

Overview Safety in the chemistry lab Experimental Chemistry Pre-lab: Percent Alcohol in Wine Chemical Communication

Safety Preparation is the key—know what you are doing! Proper attire – Goggles--$8 at Undergrad Office – NO CONTACTS – Close-toed shoes – Long pants/skirts, t-shirt at minimum No eating, drinking, gum, or smoking No horseplay—think safety

Safety: This Week in Lab Sign Safety Rules With AI’s, discuss: – Location of safety equipment – Working with chemicals – Disposal of waste – Procedure for minor cuts, spills – Meeting place for major incident Safety worksheet – Replaces quiz for this week “It’s only a flesh-wound!”

Experimental Chemistry Scientific method Experiment and theory, or theory and experiment? Pre-lab process: – Ask a question – What data needed? – How to acquire? Which of these students is getting kicked out of lab?

Percent Volume of Alcohol in Wine The question: What is the percent volume of ethanol in various samples of wine? – Quantitative analysis – Sub-questions: Red vs. white wine? Brand? What data are needed to answer our question? – Direct measurement – Indirect (calculation)

Separation: Distillation Based on physical properties Problem: Limitation of simple distillation Key to science: problem solving!

Using Reference Data Percent by weight of ethanol in mixture Density of mixture (g/mL) Percent by weight of ethanol in mixture Density of mixture (g/mL) Table 1: Weight percent and density of ethanol/water mixtures

Measurement and Uncertainty Limitations of measurements Uncertainty in values What do we need to do to acquire these data?

Calculations and Data Workup Develop a conceptual flow prior to algorithm Direct calculation vs. comparison to data Choice of measuring tools: beaker vs graduated cylinder vs volumetric flask Tools for data analysis: Excel

Chemical Communication Purposes of Formal and Informal Writing Lab notebook – Title – Purpose/Objective/Question(s) – Experimental/Methods/Procedure – Results/Observations/Changes in Procedure – Comments – Conclusion Formal Report