3h2(g)+o3(g) 3h20(g) arrow after the o3(g)whats the overall enthalpy?

The overall enthalpy of reaction will be calculated from enthalpy of formation of products and reactants.

DeltaHrxn = [Sum of enthalpy of formation of products] - [sum of enthalpy of formation of reactants]

DeltaHrxn = 3 X deltaHf (H2O) - [ 3 X DeltaH (H2) + DeltaH (O3)]

DeltaHrxn =  3 X (--242) - [ 0 + 143] = -869 kJ / mole

We can also calculate the enthalpy of reaction from bond energies

answer: you could do some invislibe ink.

explanation: i will tell you how to if u answer my question.

- calcium has greater affinity to bond with electron receptors than hydrogen does and hence, it has the ability to replace hydrogen in most of its compounds.

- lithium has 2 valence electrons in the product because it can make only 1 bond with hydrogen. beryllium has 4 valence electrons in the product because it can only make 2 bonds. it has fewer electrons than neon and can react with electron donors. each hydrogen has 2 valence electrons, the same as helium.

- the covalent bond formed between carbon and hydrogen is polar because carbon is more electronegative than hydrogen and it attracts the bonded electron pair closer to itself, thus giving hydrogen a partial positive charge.

- a hydrogen bond is a relatively weak bond that hydrogen atoms make with the electronegative atoms nitrogen, oxygen or fluorine.

so the best choice is a.) 2 calcium (ca) atoms