Phosphorus tribromide decomposes to form phosphorus and bromide, like this:

4pbr3(> p4(g)+6br2(g)

also, a chemist finds that a certain temperature at the equilibrium mixture of phosphorus tribromide, phosphorus, and bromine has the following composition:

compound pressure at equiibrium
pbr3 97.4 atm
p4 99.2 atm
br2 97.2 atm

calculate the value of the equilibrium constant kp for this reaction. round your answer to 2 significant digits.

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.