23.1.9 CIA Demonstration: Weighing on an Analytical Balance

Question 1

CIA Demonstration: Weighing on an Analytical Balance

Answer 1

• An analytical balance allows for weighing of materials to very high precision.

Question 2

note

Answer 2

• An analytical balance allows for weighing of materials to very high precision.
• The tare feature is useful to reset the analytical balance to 0.0000 g.
• Many analytical balances are sensitive enough to weigh ink written onto a piece of paper.
• Weighing papers are small squares of very thin waxed paper used for weighing out small samples of reagents.
• Weighing boats are small plastic “boats” for weighing out larger samples of reagents.
• A clean scoopula can be used to transfer a small amount of reagent to a weighing paper.
• Tapping the scoopula delivers small amounts of the sample to the weighing paper.
• In most experiments, precision in weighing is more important than accuracy. For example, if an experiment calls for 0.10 g of reagent, it is usually more important that the mass be known precisely (for example, 0.1011 g) than the mass be exactly 0.1000 g.
• Reagent can be poured directly from a reagent bottle into a weigh boat by rolling the reagent container from side to side. However, when just starting work in a laboratory, it is often easier to use a scoopula for large amounts as well as small amounts, to avoid spills.