the radioactive isotope europium decays with a first order rate constant of 0.062 year-1. What fraction of the europium in a sample is still present 55.0 years later

2ki + pb(no3)2 → 2kno3 + pbi2 determine how many moles of kno3 are created if 0.03 moles of ki are completely consumed.

Which of the following reactions represents an exothermic reaction? nh3(g) + 12.0 kcal ½n2(g) + 3/2 h2(g) ch4 + 2o2 co2 + 2h2o + 212,800 cal c + 2s cs2, h = 27,550 cal c(graphite) c(diamond), h = 0.45 kcal 2h2o 2h2 + o2, h = +58 kcal

The osmotic pressure exerted by a solution is equal to the molarity multiplied by the absolute temperature and the gas constant r. suppose the osmotic pressure of a certain solution is measured to be 12.atm at an absolute temperature of 317k. write an equation that will let you calculate the molarity c of this solution. your equation should contain only symbols. be sure you define each symbol other than r. equation: c=? definition of symbols: ? = 12 atm ? = 317 k