CHEM 201 Lecture Notes - Lecture 9: Iron(Ii) Oxide, Iron(Ii) Hydroxide, Iron(Iii) Oxide-Hydroxide
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Hydrates are ionic compounds in which the formula unit includes a fixed number of water molecules. Give the formula for each of the following ions: Give the formula for each of the following ionic compounds: potassium sulfide k2s ammonium sulfite (nh4)2so3 iron(ii) oxide feo chromium(iii) nitrate cr(no3)3. Molecular ionic (molecules) (formula units or empirical formulas) Molecular mass (amu) formula mass (amu: relative molecular (formula) mass is the mass of molecule (formula unit) expressed in amu, to calculate molecular (formula) mass we add the masses of atoms (ions) in formula. Example 1: calculate the molecular mass of c6h4cl2 (dichlorobenzene) to 5 significant digits. = 6 12. 011u + 4 1. 0079u+2 35. 453u=147. 00 u: calculate the molecular mass of h3po4 to 3 significant digits. = 3 1. 01u + 1 31. 0u+4 16. 0u=98. 0 u: calculate the formula mass of (nh4)2so4 to 3significant digits. ={ [1 14. 0u + 4 1. 01u] 2}+{1 32. 1u+4 16. 0u}=132 u: calculate the formula mass of nahco3 to 5 significant digits.
