What do the symbols tell you about the conditions
of the reactions shown to the right? Check all of
the boxes that apply.
3H, (g) +N (9) 450°C 2NH, (g)
(2) 250, (g) + O2(g) Os 250, (g)
The products and reactants of both reactions
are gases.
Reaction 1 occurs at high pressure.
Reaction 2 makes a small amount of an
additional product.
A catalyst is used for reaction 2.

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.