In this exercise you are asked to calculate the enthalpy change of lime burning, using the enthalpy values of the intermediary reactions. The Hess cycle diagram of the limestone cycle is enclosed for assistance. CaCO3 ↔︎ CaO + CO2 △H1 = ???

CaO + H2O = Ca(OH)2 △H2 = -65 kJ/mol

Ca(OH)2 + CO2 = CaCO3 + H2O △H3 = -115 kJ/mol

ca has a crystalline lattice with positive ions (since it is a metal, metals are positively charged) and electrons flow freely in its structure since the ca atoms have a large nuclear radius so the electrons are not tightly held, therefore the electrons can flow freely since they are not being highly attracted by the nucleus. moreover, one of the properties of metals are that they are conductors of electricity, thus proving ca is the element.

the seeing the electronic configuration we can say that the element is fluorine.

fluorine is the most electronegative element in the periodic table.

but by only seeing the configuration we cannot say about its reactivity because we don't know if its configuration after excitation or by addition of electrons.

but if not then, it is the lightest halogen and exists as a highly toxic pale yellow diatomic gas at standard conditions. as the most electronegative element, it is extremely reactive: almost all other elements, including some noble gases, form compounds with fluorine.

gasoline is a mixture. it contains several different kinds of compounds that can be present in a variety of ratios.