Pesach is a VERY busy time for women. There is much organizing, cooking, and cleaning! It also can be a time of confusion with so many different halachot. It is very important to sit down as a couple (with your spouse) or as a community and determine what your family's chalakah will be concerning Pesach and keep a journal about your discussion and activities.
One of the big issues we discussed is "what exactly is leaven?" Scripture uses two different words for "leaven": chametz and seor.
Seor is a substance which, through fermentation, makes dough rise. Yeast, baking powder, and baking soda are all leavening agents. However there are "kosher for passover" baking powder and soda available.
Chametz is any product made with "seor" in it. White, fluffy Wonderbread, donuts, and bagels are "chametz" because they have leaven in them.
Scripture tells us that leaven [seor] should be removed from our homes on the first day (Exodus 12:15) and that it should not be in our homes for seven days (Exodus 12:19). Nothing leavened [chametz] should be seen among you or within your borders (Exodus 13:7). We should not eat anything leavened [chametz] (Exodus 12:20). See The Feast of Unleavened Bread for more details.