A hydrocarbon Y contain 1.44g of carbon 0.36g of hydrogen (it has relative molecular mass of 30) 1 Derive the empirical formula of Y and hence it's relative molecular mass
2 State the constant composition or define proportion.

Compare and contrast physical changes with chemical changes.

For each of the compounds below, show that the charges on the ions add up to zero. a. kbr b. cao c. li(2)o d. cacl(2) e. alcl(3)

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.