Calculate the enthalpy change for the reaction 2 hcl → h2 + cl2 1. +184 kj/mol of rxn 2. +428 kj/mol of rxn 3. 0 kj/mol of rxn 4. −184 kj/mol of rxn 5. −244 kj/mol of rxn

Ants live on acacia trees in south america. the ants feed on sugars secreted by the trees. the trees provide room for the ants to live. the ants sting any other insect or animal that comes to eat the trees. what type of relationship is this?

How many absorptions would you expect to observe in the 13c nmr spectra of the following molecules? a) 3-chloropentane b) cis-4-methyl-2-pentene

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.