How does the modern periodic table of the elements differ form mendeleyev's chart?

In science class richard learns that a substance has a boiling point of 230 fahrenheit his teacher ask him to convert this temperature to degrees celsius what is the boiling point of his substance in degrees celsius

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.

Apropane torch is lit inside a hot air balloon during preflight preparations to inflate the balloon. which condition of the gas remains constant