Consider the reaction:2ClF3(g) + 2NH3(g) –> N2(g) + 6HF(g) + Cl2(g)When calculating the ∆H°rxn, why is the ∆Hf° for N2 not important?

In which group do all the elements have the same number of valence electrons?

An atom of fluorine contains nine electrons. How many of these electrons are in s orbitals?

Using the following thermochemical data, calculate ∆Hf° of Tm2O3(s). 2TmCl3(s) + 3H2O(l) –> Tm2O3(s) + 6HCl(g) ∆H° = 388.1 kJ/mol 2Tm(s) + 3Cl2(g) –> 2TmCl3(s) ∆H° = –1973.2 kJ/mol 4HCl(g) + O2(g) –> 2Cl2(g) + 2H2O(l) ∆H° = –202.4 kJ/mol

Consider the following representation of a 2p-orbital:Which of the following statements best describes the movement of electrons in a p-orbital?

B2  (Show your work on your Free Response Paper for full credit) Using the following thermochemical data: 2Cr(s) + 6HF(g) –> 2CrF3(s) + 3H2(g) ∆H° = –691.4 kJ/mol 2Cr(s) + 6HCl(g) –> 2CrCl3(s) + 3H2(g) ∆H° = –559.2 kJ/mol calculate ∆H° for the following reaction:CrF3(s) + 3HCl(g) –> CrCl3(s) + 3HF(g)

What is the energy of a photon of blue light that has a wavelength of 453 nm?

Germanium has __________ in its 4p orbitals.

Consider the following orderings. I. Na+ < Mg2+ < Al3+ < Si4+ II. Be < Mg < Ca < Sr III. I < Br < Cl < F IV. Al < Si < P < Cl Which of these give(s) a correct trend in ionization energy?

Given the equation S(s) + O2(g) –> SO2(g), ∆H = –296 kJ, which of the following statement(s) is (are) true?  I.  The reaction is exothermic.II.  When 0.500 mole sulfur is reacted, 148 kJ of energy is released.III.  When 32.0 g of sulfur are burned, 2.96 x 105 J of energy is released.