Salah consists of equal units, each of which is called Rak`ah in Arabic.
Each Rak`ah (unit or cycle of prayer) is made up of several postures, including standing, bowing, prostrating, and sitting. It is performed in a continuous manner along with reciting Al-Fatihah (the first Qur’anic chapter) and any other memorized portion of the Qur’an, in addition to specific phrases of glorification, praise, and supplication.
The Number of Rak`ahs of Each Obligatory Prayer:
• Fajr (Dawn) Prayer: Two units.
• Zuhr (Noon) Prayer: Four units.
• `Asr (Afternoon) Prayer: Four units.
• Maghrib (Sunset) Prayer: Three units.
• `Isha’ (Night) Prayer: Four units.
Difference between Dua’ and Salah:
Dua’ means literally supplication; calling out to Allah, the Provider of all things, for whatever needs we have.
It has no prescribed form; it can be said at any time, day or night, in any language. It is spontaneous, using whatever words or phrases come to mind (one’s own words or memorized supplications from the Qur’an and Sunnah) and does not require performing ablution or facing the Qiblah.