In this paper we describe the chemical reactions of leavening agents in baking biscuits on a sound thermodynamic basis. The model is part in a sequel targetted at physical understanding of biscuit baking with the purpose of reformulation of biscuits with respect to sucrose and sodium levels. The chemical leavening gases. CO2 and NH3. https://www.bekindtopets.com/top-super-Harry-Potter-Hufflepuff-Big-Bang-Lite-Headband-quick-super/