If the crucible cover falls and breaks during the heating, do you have to start

Question

If the crucible cover falls and breaks during the heating, do you have to start the experiment over ' again? Why or why not? Defend your answer. What is the purpose of adding water during the experimental procedure? Show by chemical equations what occurs when water is added. Why will the crucible and its contents gain mass when heated? Chemically, what has happened? A student did a similar experiment with Ag and O to produce silver oxide. Here is the data from the experiment. Mass of crucible and cover: 29.307 g Mass of crucible, cover, and silver: 30.958 g Mass of crucible, cover, and silver oxide: 31.080g Use these data to determine the empirical formula for silver oxide.

Explanation / Answer

4) Yes, we need to start the experiment again , as oxygen level will increase in it . This will disturb the whole calculation

6) If the experiment is determination of emperical formula of any molecule than

The Ag reacts with the oxygen in the air. So, all the Ag stays in the crucible, but some oxygen (forming AgO) and a tiny bit of nitrogen (forming Ag3N) are added. The result is that the crucible gains weight.

7) Mass of crucible and cover = 29.307 g

Mass of crucible cover and silver = 30.958

so mass of silver = 30.958 - 29.307 = 1.651 grams

Mass of silver oxide = 31.080 - 29.307 = 1.773

The mass of oxygen = 1.773-1.651 = 0.122

Moles of oxygen = 0.122 / 16 = 0.0076

Moles of silver = 1.651 / 108 = 0.015

So ratio of Silver to oxygen = 0.105 / 0.0076 = 2:1

Emperical formula = Ag2O

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