After 4797 years 1/8 of a radioactive sample remains what is it

When microscope slides are stained to show blood cells, the small red blood cells that appear on the slides are much numerous than the large white blood cells. this supports the concept that

Which of the following reactions is endothermic? h2(g) + ½ o2(g) h2o(g), h = -57.82 kcal ½n2(g) + o2(g) + 8.1 kcal no2(g) ½ n2(g) + 3/2 h2(g) nh3(g) + 11.0 kcal c(diamond) + o2(g) co2, h = -94.50 kcal

Write the balanced chemical reaction for the formation of fe2(so4)3 from fe2o3 and so3 and determine how many moles of fe2(so4)3 are formed when 12.7 mol of so3 are reacted.