I have a question from OCR Chemistry A-level attached.
I know instantly that C and D are wrong, leaving A and B.
The answer is A, but I'm confused why the enthalpy change is negative, not positive. Can someone please explain why the enthalpy change is negative?
The reaction is exothermic as bonds are being formed. CaCl2 is formed in the process, as well as CO2 and H2O.
The reaction has a positive entropy change as the system is becoming more disordered; going from a solid state to a liquid/aq/g state on the right hand side.
Is sodium hydrogencarbonate an acid? It can, afterall, donate a proton. Which surely makes it an acid. But it dissolved into water to make pHs greater than 7 (@ 25 oC).