Heats of formation calculation:

Tables are available for heats of formation of common compounds and ions in aqueous solution in most general chemistry textbooks. Calculate DH for the following reaction: 8 Al(s) + 3 Fe3O4(s) --> 4 Al2O3(s) + 9 Fe(s)

chem problems

. The Zinc in a 1.200g sample of foot powder was precipitated as ZnNH4PO4. The strong heating of the precipitate yielded 0.4089g of Zn2P2O7. Calculate the mass percent of zinc in the sample of foot powder. 2. A mixture contains only sodium chloride and potassium chloride. A 0.1586g sample mixture was dissolved in water. It took 22.90mL of 0.100 M Silver I nitrate to completely precipitate all of the chloride present. What is the composition (by mass) of the mixture?

Chem problem

An electric furnace produces phosphorus by the following reaction: Ca3(PO4)2(s) + C(s)+SiO2(s)= CaSiO3(s)+CO(g)+P(I) An initial reaction mixture contains 1500g calcium phosphate, 250 g carbon and 1000g silicon dioxide. a) What is the limiting reactant? b) What is the theoretical yield of phosphorus? c) After the reaction of the slag (solid residue) was analyzed. It contained 3.8 % Carbon, 5.8 % Phosprorus, and 26.6 % Calcium by mass. What was the actual yield of phosphorus? What was the percent yield?

thermochemistry

I need to explain qualitatively the relationship between hydration enthalpy and ion radius (for group 1 cations compared to group 7 anions). I also need to explain the relationship between lattice energy and ion radius of sodium salts compared to cloride salts. I was also wondering why the molar heat of solution depends on the final concentration of a solution. thank you

Converting units

Hi. I do not understand the process for converting...can you please explain step by step? Use the appropriate symbol (>,<, or =) 303 m ______303X10^3km 1.50 cm^3_______1.50X10^3nm^3 Thank you.