brought to you by Kollel Iyun Hadaf of Yerushalayim
& Revach l'Neshamah - http://www.revach.net
1. The status of dough that is stuck to a trough with regard to Tum'ah during ordinary days of the year differs from its status during Pesach.
2. The Mishnah discusses how to determine whether dough is Chametz when we are unsure of its status.
3. The Gemara explains how we determine whether dough has become Chametz when no other dough was kneaded at the same time.
4. The Gemara lists various laws that depend on the time that it takes one to walk four Mil (i.e., 72 minutes).
5. The Mishnah discusses what one should do with regard to separating Chalah from dough that became Tamei on Pesach.
A BIT MORE
1. The Gemara discusses whether a Tamei object that touches the dough causes the trough to become Tamei as well. The Gemara explains that if the owner does not want the dough to be there, then the trough remains Tahor. If the owner wants the dough to remain there (such as to plug a hole in the trough), then the entire trough becomes Tamei.
2. If other dough was kneaded at the same time as the dough in doubt, and it has already become Chametz, then we presume that this dough is also Chametz.
3. If the dough has been left for the time it takes to walk one Mil (i.e., eighteen minutes), it is presumed to be Chametz.
4. For example, if someone is traveling and needs to pray, if -- by walking up to four more Mil he will find a Minyan with which to pray, he must do so.
5. Rebbi Eliezer: One should bake all of the dough so that it should not become Chametz, and only afterwards separate Chalah. Ben Beseira: One should put the dough into cold water. Rebbi Yehoshua: There is no prohibition if it becomes Chametz after Chalah is separated, since Chalah does not belong to the person.
Next Daf Index to Revach for Maseches Pesachim