How many atoms of mercury are required to produce 3.49 L of H2 gas (density = 0.0899 g/L
according to the balanced chemical reaction:
2Hg(l) + 2 HNO3(aq) → Hg2(NO3)2(aq) + H2(g)

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

Asample of radium-226 will decay 1/4 of its original amount after 3200years. what is the half-life of radium-226?

1. explain hydrogen peroxide, h 2 o 2 properties and decomposition reaction. 2. describe how each of the following natural cycles plays a part in earth’s climate system. (a) the water cycle (b) the carbon cycle