Consider two reactants (A and B) that when mixed form a precipitate C, which can be filtered, dried, and then weighed. Carlos attempts to find the stoichiometric ratios in which A and B mix, by mixing different volumes of the same concentration of solutions of A and B (0.50 M). He records the following data: Run Vol A (mL) Vol B (mL) Mass C (g)1 10.0 10.0 1.172 20.0 10.0 2.33 3 30.0 10.0 3.504 40.0 10.0 3.50 Which of the compounds (A or B) is the limiting reagent? Run Limiting Reagent 1 2 3 4What is the stoichiometric ratio in which A and B combine?

Tooth enamel consists mainly of the mineral calcium hydroxyapatite, ca_10(po_4)_6(oh)_2. trace elements in teeth of archaeological specimens provide anthropologist with clues about diet and diseases of ancient people. students at hamline university measured strontium in enamel from extracted wisdom teeth by atomic absorption spectroscopy. solutions with a constant total volume of 10.0 ml contained 0.726 mg of dissolved tooth enamel plus variable concentrations of added sr. added sr find the concentration of sr in the 10 ml sample solution in parts per billion = ng/ml. find the concentration of sr in tooth enamel in parts per million = mu g/g.