Why didn't Klal Yisrael prepare any bread the night before they left Mitzrayim? The pasuk in Shemos (12:39) as translated by mechon-mamre writes,
וַיֹּאפוּ אֶת-הַבָּצֵק אֲשֶׁר הוֹצִיאוּ מִמִּצְרַיִם, עֻגֹת מַצּוֹת--כִּי לֹא חָמֵץ: כִּי-גֹרְשׁוּ מִמִּצְרַיִם, וְלֹא יָכְלוּ לְהִתְמַהְמֵהַּ, וְגַם-צֵדָה, לֹא-עָשׂוּ לָהֶם. And they baked unleavened cakes of the dough which they brought forth out of Egypt, for it was not leavened; because they were thrust out of Egypt, and could not tarry, neither had they prepared for themselves any victual.
It seems the nation was caught unaware that they were leaving Mitzrayim the next morning on short notice. No one knew of the imminent exodus?