# It is important to stay consistent with the balance

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It is important to stay consistent with the balance you decide to use. Specific Waste & Safety: All water used in this part can go down the sink. IV. DATA COLLECTION & CALCULATIONS For this part of the investigation we recommend that you record the following data and calculations . Experimentally measured number of drops Mass of dry container Mass of container with water ????𝑖?? = 𝑀𝑎?? 𝑉????? % ?𝑖???????? = | 𝑉𝑎??? 1 − 𝑉𝑎??? 2 | 𝐴???𝑎?? ?? 𝑉𝑎??? 1 𝑎?? 2 × 100
Arizona State University CHM 113 S19 School of Molecular Sciences 9 Mass of one drop of water Table 5: Measurements for an average volume and mass of one drop of water . Container used:________________________ Trial # Experimentally Measured Number of Drops Mass of Empty Dry Container (g) Mass of Full Container with Water (g) Mass of One drop of Water (g) Calculated Volume of one drop (mL) Calculated number of drops/mL (drops/mL) 1 2 Averages: Procedure for Part 3: Measuring Solids with an electronic balance I. OBJECTIVES Learn how to correctly use an electronic balance to weigh masses. Learn how and why to use the “TARE” or “Re - Zero” function on an electronic balance. Be able to calculate amount of mass loss, if any, when transferring a solid to a reaction container. II. PROCEDURE DEVELOPMENT Develop and write a procedure to exactly measure 0.100 g, 1.000 g, and 10.000 g of sand by using a secondary container. You should be able to determine the amount of sand lost, if any, when you transfer each of your measured quantities to a reaction container. Important things to consider when writing your procedure: Collect an appropriate amount of solid in a secondary container to bring to the balance room. o Ex: Place about 3 scoops of sand into a 50 mL beaker with a clean, dry scoopula. You should never weigh the solid directly on the balance pan, you can use a weighing boat or something such as a watch glass or clean, dry glass beaker of sufficient size. o Decide what you will use. Read the background sec tion “ Performing Measurements Using an Electronic Balance” to become familiar with how to use and tare/zero the balance when measuring mass. Determine the best way to add and remove excess sand when performing your measurements. Keep a record of all of your measurements with the correct number of significant figures.
Arizona State University CHM 113 S19 School of Molecular Sciences 10 III. EXPERIMENTAL CONSIDERATIONS How to handle solid reagents from a reagent bottle. The sand is located in the fume hood and should be treated as if it were a chemical reagent. The stock chemical container should never leave the hood. An approximate amount of material should be dispensed in the hood to a secondary container to bring with you to the balance. o Use the spatula or scoopula provided to dispense the solid into your secondary container to avoid contaminating the stock reagent.