TECH 382: Tranafer and Measurement of Chemicals 119 date Pre-Laboratory Assignme
ID: 573909 • Letter: T
Question
TECH 382: Tranafer and Measurement of Chemicals 119 date Pre-Laboratory Assignment 1· (1) Whymust the glass stopper of a reagent bot- tle never be placed directly on the laboratory bench? 3. How should a solution or liquid be poured from one container to another? (2) How should a stopper be handled after it has been removed from a reagent bottle? 4. (1) A student found that a 1.0-mL sample c water contained 20 drops. How many drops would b in 5.0 mL of water? 2. (1) What is meant by a meniscus? (2) Based on your preceding answer, how milliliters of water correspond to 35 drops? (2) When you are making volume measure- how should you read the level of the liquid? ments,Explanation / Answer
1. Because the stopper might get contaminated and therefore you could contaminate the reagent with impurities , also the stopper could contaminate the bench
2. The stopper should be held during the transfer until you put it back on the bottle.
3. You should use a funnel and a glass (stirring rod) to pour down the liquid into another container in order to avoid splashing
4. 1 ml has 20 drops so 5 ml should have:
(20 d / 1 ml) * 5 ml = 100 drops
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