0 A student combines Substance X with Substance Y. The two substances react completely to form Substance Z. The student measures an increase in temperature as the reaction occurs. What happens to the amount of chemical energy during the chemical reaction? *

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.

The earth's surface is (science) a: studied using seismic waves b: constantly changing over time c: only studied indirectly d: the same today as million of years

Most points for whoever anwers i need your which is not an isotope of carbon? a. carbon-6 b. carbon-12 c. carbon-13 d. carbon-14