Radioactive carbon-14 has a half life of 5730 years. suppose a peice of wood has a decay rate of 15 disintegrations per minute. how many years would it take for the rate to decrease to 4 disintegrations per minute?

Agas mixture with a total pressure of 745 mmhg contains each of the following gases at the indicated partial pressures: co2, 245 mmhg ; ar, 119 mmhg ; and o2, 163 mmhg . the mixture also contains helium gas. part a what is the partial pressure of the helium gas? phe p h e = nothing mmhg request answer part b what mass of helium gas is present in a 10.2-l sample of this mixture at 283 k ? m m = nothing g request answer

The wave shown on the electromagnetic spectrum disturb the medium it passes through a)different frequency. b)the same frequency .

Acompound has a molecular weight of 12.124 atomic mass units and the empirical formula c3h40. what is the molecular formula of the compound?