How to be a Successful Organic Chemist

22 3.2 Getting the chemicals to your reaction flask: pouring, syringes and weighing Laboratory chemicals are typically stored, and dispensed, in a variety of containers and locations.Therefore, early hurdles in every experiment are 1) figuring out how to obtain the desired amount of the chemical, 2) figuring out how to transfer this material safely from the location where it is obtained to the location where it will be used, and 3) figuring out how to put the materials in the apparatus. Solids: Solids are usually stored in wide-mouthed bottles and weighed before use. The solid is weighed us- ing a weigh boat, or a piece of weighing paper, and it is usually possible to transfer the solid from the bottle to the boat (or paper) using a clean spatula or lab scoop. A good laboratory practice is to remove the weigh boat (or paper) from the balance each time you add solid to it, and then return the boat (or paper) to the scale. This practice reduces the likelihood that any chemicals will get spilled on the balance. Liquids: Liquids are typically more difficult to handle, and the appropriate method will depend on how much liquid is needed and the specific properties of that compound. In most cases, it will be safer and more convenient to obtain a specific volume instead of weighing the liquid. For reagent quantities, a pump sys- tem is often employed to deliver calibrated volumes, or a graduated cylinder can be used. Solvents, whether needed for reactions or extractions, tend to be used in larger quantities and a graduated cylinder will nearly always be more conventient. 3.3 Washing your glassware Cooking a dinner creates dirty dishes and doing an organic chemistry lab experiment creates dirty glass- ware. Cleaning your glassware properly is an important aspect of the lab experience. This should be a prior- ity, as impurities or trace amounts of chemicals from previous labs can ruin or complicate your experiment. Starting with visibly dirty or contaminated glassware is also considered poor lab practive, as the outcome of the reaction cannot be trusted: was the outcome due to the reagents you combined, or was it in some way influenced by the contaminants? We will cover two good cleaning protocols, one for glassware that has been used for organic samples, and one for inorganic solutions. A good cleaning protocol for glassware that has contained organic solutions or samples: the glassware is rinsed with acetone in the hood, and the contaminated acetone solution is then poured into the organic waste. The glassware is then allowed to air dry. If the glassware is still dirty, try this: wash with soap and (C) Using your free hand, hook your thumb under the second glove. Pulling upwards, remove the glove com- pletely. (A) Start by hooking a finger into the outside of the glove. (B) Gently pulling upwards, remove the first glove. Figure 3.1. A safe way to remove laboratory gloves.