What is the standard free energy change (in kilojoules) for the following reaction? 2SnO2(s)→2SnO(s)+O2(g) ΔG∘298,SnO2(s)ΔG∘298,SnO(s)=−515.8k Jmol=−256.9kJmol

What is the number of moles of chemical units represented by 9.03x10^24? and how do i show work? (dumb it down )

8) a mixture of he, ne and ar has a pressure of 7.85 atm. if the ne has a mole fraction of 0.47 and 8) ar has a mole fraction of 0.23, what is the pressure of he? a) 4.2 atm b) 3.7 atm c) 5.5 atm d) 2.4 atm e) 1.8 atm

With the largest atoms and the smallest number of valence electrons and with the smallest atoms and the greatest number of valence electrons are the most reactive. a. nonmetals; metals b. nonmetals; transition elements c. transition elements; metals d. metals; nonmetals