Which of the following metals is the most chemically reactive?  : Sr, Mn, Be, or Cr  Which of the following nonmetals is the least chemically reactive? : N, P, B, or Cl

Carbon naturally occurs in two forms: diamond and graphite. Why do these two forms have very different properties? The key difference is that diamonds have other elements bonded within their structure. The differences are explained by the number of covalent and ionic bonds within each substance. The differences are explained by the density: graphite is very high and diamond is much lower. The differences are explained by how the carbon atoms within each substance are covalently bonded together.

The first laboratory experiments to produce compounds containing noble gas atoms aroused great excitement, not because the compounds might be useful but because they demonstrated that the noble gases were not completely inert. Since that time, however, important uses have been found for a number of noble gas compounds. For example, xenon difluoride, XeF2, is an excellent fluorinating agent (a substance that adds fluorine atoms to other substances). One reason it is preferred over certain other fluorinating agents is that the products of its fluorinating reactions are easily separated from the gaseous xenon. The following unbalanced equation represents one such reaction: S3O9 + XeF2 → S2O6F2 + Xe Balance this equation. What is the minimum number of moles of XeF2 necessary to react with 4 moles of S3O9? What is the maximum number of moles of S2O6F2 that can form from the complete reaction of 4 moles of S3O9 and 7 moles of XeF2? How many moles of xenon gas form from the complete…

Cyanamide is a compound containing two hydrogen atoms and some amount of C and N. There are a total of 5 atoms in the compound. The products of combustion were found to be CO2, NO2, and H2O. If the enthalpy of combustion for cyanamide is – 671.9 kJ/mol and the enthalpy of formation is 58.8 kJ/mol, what is the chemical formula for cyanamide? ( ΔfH (CO2) = - 393.51 kJ/mole; ΔfH (NO2) = + 33.10 kJ/mole; ΔfH (H2O) = - 241.826 kJ/mole)

Consider an ionic compound, MX3, composed of generic metal M and generic gaseous halogen X. The enthalpy of formation of MX3 is Δ?∘f=−925 kJ/mol. The enthalpy of sublimation of M is Δ?sub=175 kJ/mol. The first, second, and third ionization energies of M are IE1=579 kJ/mol, IE2=1677 kJ/mol, and IE3=2479 kJ/mol. The electron affinity of X is Δ?EA=−369 kJ/mol. (Refer to the hint). The bond energy of X2 is BE=179 kJ/mol. Determine the lattice energy of MX3.

8. Given the following six figures (at room temperature). Match them to the following compounds/molecules: HI, P₂H4, Fe₂O3, Na2S (cation dark sphere, anion open sphere), CaF2(cation dark sphere, anion open sphere), KF.

The ionic radii of element E and a different metallic element, M, are shown in the following table: Both elements form oxides, E2O and MO. If lattice energy is defined as the energy required to separate an ionic solid into individual separate gaseous ions, would the lattice energy of MO be less than, equal to, or greater than the lattice energy of the oxide E2O? Justify your answer in terms of Coulomb's law

Write the empirical formula of at least four binary ionic compounds that could be formed from the following ions: Fe+2, Al+3, I−, S−2

6. Zn(s) + O2(g)