Consider the reaction described by the following chemical equation. 2Ag2S(s)+2H2O(l)⟶4Ag(s)+2H2S(g)+O2( g)ΔH∘rxn=595.5kJmol The change in enthalpy for this reaction can be determined theoretically by using the standard enthalpies of formation for the species involved. ΔH∘rxn=∑nΔH∘fproducts−∑nΔH∘freactan ts What is the value for the standard enthalpy of formation for Ag(s) that would be used in the equation above?

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 grooves or folds of the brain are called

Sally is making a model of a magnesium atom with an atomic mass number of 24 for her chemistry class. she has foam balls for the protons, neutrons, and electrons. she has added 6 neutrons to her model so far. how many more neutrons does she need to add to complete her neutral atom of magnesium?