Which microscopic representation best represents a homogeneous mixture?

For the decomposition of mercury(II) oxide, HgO, to mercury and oxygen: 2HgO(s) → 2Hg(l) + O2(g)               What is the standard change in entropy for this reaction? So / J∙mol–1∙K–1 HgO(s) 70.29 Hg(l) 76.02 O2(g) 205.14  

When this equation is balanced with the smallest set of whole numbers, what is the coefficient for N2H4? ___N2H4(g) + ___N2O4(g) → ___N2(g) + ___H2O(g)

For the reaction: H2(g) + C2H4(g) → C2H6(g) a series of experiments were conducted as shown in the table. If the rate law was found to be rate = k, what is the missing initial rate (marked with the “?” in the table)? Initial rate / M·s–1 0 / M 0 / M 0.0148 0.125 0.125 0.0301 0.250 0.125     ? 0.250 0.250  

For the oxidation of iron to form iron(III) oxide: 4Fe(s) + 3O2(g) → 2Fe2O3(s) ΔSo = –549.73 J/K at 298 K The enthalpy of formation of Fe2O3(s) is –824.2 kJ/mol. What is the standard change in Gibbs free energy for this reaction at 298 K?  

Which numerical process will determine the mass (in grams) of carbon in 1.312 mol of acetaminophen (C8H9NO2)?  The molar mass of acetaminophen is 151.18 g/mol.

What is the energy of a photon with a wavelength of 245 nm? 

Of the substances below, which will hydrogen bond with water?  

A Bohr model of an atom of hydrogen is shown in the figure. Which transition(s) depicted by arrows result in energy emission, found as a line in the atomic emission spectrum?  

How much time (in seconds) is needed to deposit 0.0125 g of chromium from a solution of Cr(NO3)3 with a current of 1.50 A? The molar mass of chromium is 52.00 g/mol.