Use your heat of formation (thermodynamic data) table to calculate the heat of the following reaction:
CuO (5)+CO2 (8)->CuCO2 (s)

AH = ?
178.5 kJ
45.5 kJ
-45.5 kJ
-178.5 kJ

It is a mixture. simply put, a compound must be pure, that is, of only one chemical structure and composition. a mixture is made of different chemical substances (i.e. elements, molecules, compounds) that are not chemically bonded to each other, but instead physically grouped together, as in the case of gasoline (a homogeneous solution).

Bromine has atomic number  35  which means there are  35 protons  and  44  neutrons to give a total of 79 nucleons. the fact that it's a positive ion means that it has lost an electron; so there'll be  34 electrons.