Why are alloys used in a ballpoint pen?

Increasing the substrate concentration in an enzymatic reaction could overcome which of the following? a) the need for a coenzymeb) allosteric inhibitionc) competitive inhibitiond) insufficient cofactors

What is the mass of oxygen gas is consumed in a reaction that produces 4.60mol so2

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.