Your mommy buys you a helium balloon at the circus. It has a volume of 4.00 liters at STP. What mass of helium, expressed in grams, does this balloon contain? Show your work please!

What is the ima of the 1 st class lever in the graphic given? 2 3 0.5

Identify two types of chemical bonding in the source of dietary potassium

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.