IMAGE. Potential weighing vessels.
(from upper left: Erlenmeyer flask, beaker, and plastic weighing boat)
A weighing vessel should be chosen to protect the balance from chemical corrosion. Balances are expensive and chemicals spilled on the balance may corrode the delicate mechanism, causing readings to be incorrect or preventing the balance from working at all. Spills may result from accidental delivery or unanticipated vigorous chemical reactions.
Potential weighing vessels include beakers, Erlenmeyer flasks, or commercially available weighing boats. Selection of an appropriate container is dependent upon the subsequent steps of the experiment.
A laboratory procedure instructs you to weigh approximately 0.3 g copper and cover it with 10 mL of 6 M nitric acid. You know that the reaction between copper and nitric acid produces nitrogen dioxide, a toxic gas. Which vessel will you choose to weigh the copper? Answer
The copper should be weighed in an Erlenmeyer flask, since the reaction in which it will subsequently be used produces a gas.
IMAGE. An Erlenmeyer flask.
Alternatively, the copper could be weighed in a weighing boat and quantitatively transferred to the Erlenmeyer flask. (Note: This reaction like any reaction that produces a hazardous substance, should be performed in a fumehood.)