1. Suppose you want to know the formula of a hydrate of chromium(III) fluoride. If you heat 1.787g of the hydrate until all of the water is vaporized, the mass of anhydrous CrF3 is 1.195g. What is the formula of the hydrate, i.e. what is the value of x in CrF3xH2O ? (The formula weight of anhydrous chromium(III) fluoride is 108.99g/mol ) 2. Balance the following equations by supplying the lowest whole numbers for w,x,y, and z : (a) wK+xSKyK2S (b) w B3H3+xO2yB2O3+zH2O (c) w B2H6+xO2yB2O3+zH2O 3. The elements oxygen and iron react to give iron(II) oxide according to the balanced equation: O2+2Fe2FeO Suppose you have 0.7574molO2. (a) How many moles of Fe are needed for complete reaction? (b) What mass of FeO, in grams, can be produced? (The molar mass of FeO is 71.8464g/mol ). 4. Manganese metal reacts with nitrogen according to the following unbalanced equation: Mn(s)+N2(g)Mn1N2(s) Suppose you want to make 7.90g of manganese(II) nitride. (a) What mass of manganese metal is needed? (b) What mass of nitrogen is needed? (c) If only 5.97g of manganese(II) nitride is obtained, what is the percent yield of Mn3N2 ? Formula weights (g/mol):Mn54.938N228.0134Mn3N2192.83 5. An unknown element reacts with bromine to give the bromide, MBr. If 2.170g of the unknown element gives 15.785g of MBr4, what is the element? (Give the symbol.) 6. CuCl2 reacts with Na2AsO4 to produce Cu3(AsO4)2 according to the equation 3CuCl2(aq)+2Na2AsO4(aq)Cu(AsO4)2(s)+6NaCl (aq) (a) Which reactant is limiting if 1.626g of CuCl2 and 2.303g of Na3AsO4 are allowed to react? (b) What mass of Cu3(AsO4)2 can be produced? (c) What mass of the excess reactant remains when the reaction is complete? Formula weights (g/mol): CuCl2134.4514Na5AsO4207.8886Cu3(AsO4)2468.48 7. Elemental phosphorus is produced by the reaction, 2Ca3(PO4)2+6SiO2+10C6CaSiO3+10CO+P4 Suppose that you have 6.00 moles of Ca3(PO4)2,26.0 moles of SiO2, and 32.0 moles of C. (a) Which reactant is limiting? (b) What are the maximum amounts (in moles) of CaSiO3,CO, and P4 that can be produced from these amounts of reactants? 8. Give the formulas and names of the soluble and insoluble products that form when aqueous solutions of the following reactants are mixed